Why a Person Cheats: The Neuroscience & Psychology of Infidelity
Table of Contents
The Real Reasons People Cheat: Infidelity and the Brain
Infidelity evokes strong emotions, and few examples have captured public attention as vividly as last summer’s viral scandal.
The married former CEO of tech company Astronomer was seen on a Coldplay concert screen. He was leaning close to his mistress, who was also the company’s HR chief. The moment the couple recognized themselves on the giant kiss cam, they quickly pulled away. But not before Chris Martin, the band’s lead singer, quipped, “Either they’re having an affair or they’re just really shy.”
It was, of course, an extramarital affair. The moment spread across social media and news outlets within hours, giving the world a front-row seat to the betrayal. Watching it unfold in real time sparked intense and wide-ranging reactions.
Share on X: Neurotransmitters, reward systems, emotional regulation, and overall brain function can strongly influence decision-making and behavior—and this influence can increase an individual’s risk of cheating.
Yet, shocking as it may be, infidelity is far from rare. A 2022 survey found that 20 percent of men and 13 percent of women said they had an affair while married. When so many men and women step outside their committed relationships, it begs the question, why do people cheat? And more pertinent to the work of Amen clinics, could brain chemistry play a role in infidelity?
Infidelity is complex, and many reasons exist for why a person cheats. However, there is a neuroscience of infidelity. Neurotransmitters, reward systems, emotional regulation, and overall brain function can strongly influence decision-making and behavior—and this influence can increase an individual’s risk of cheating.
In this article, you will learn what causes infidelity, including how brain chemistry plays a role. You will also discover the varied reasons people cheat. Finally, we will explore how couples can heal after cheating.
The Brain Chemistry Of Attraction And Infatuation
Mother Nature knew what she was doing when she made the strong mix of brain chemicals that cause love and infatuation.
It appears that romantic love and infatuation are not so much an emotion as they are motivational drives. They are built into the brain’s reward system. These feelings intensify and compel lovers to seek mating partners.
The chemicals that stimulate the motivation and drive system in the brain are the neurotransmitters epinephrine, dopamine, serotonin, and phenylethylamine (PEA).
Here’s a closer look at these neurotransmitters of love:
The Neurochemistry of Love and Lust
| Neurotransmitter | What It Does |
|---|---|
| Epinephrine | Causes an adrenaline rush that increases heart rate, raises blood pressure, and quickens breathing. |
| Dopamine | Associated with pleasure, motivation, and concentration; activates the brain’s reward centers. High levels are linked to attraction and feeling sexy. |
| Serotonin | Known as the “feel-good” neurotransmitter, yet drops sharply during new love, likely causing obsession, anxiousness, and constant thoughts about a new partner. |
| PEA | An adrenaline-like substance that speeds communication between nerve cells. Triggered by attraction and known as the “love molecule,” it initiates surges of norepinephrine and dopamine that produce euphoria and infatuation. |
The enjoyable feelings and motivations behind romantic love come mainly from a mix of strong neurohormones in your brain. That may be why some neuroscientists say that love “blooms” in the brain!
But blossoms do not last forever, and neither does the high of new love. Neuroscientists have determined that after a period of anywhere from 6 months to 2 years, the brain downshifts its response, and the production of stimulating chemicals and levels of neurotransmitters like PEA start to drop off. It is the body’s innate wisdom to turn down the volume because it cannot maintain the lust-crazed state forever, or people would eventually collapse with exhaustion!
When the amazing high and trance-like bliss of falling in love and being infatuated with each other eventually fades, couples generally either progress into deeper love and commitment or make the decision to break apart and detach.
Many couples therapists say that many unnecessary divorces and breakups happen during this time. People often mistake the lack of intensity and excitement as a sign that they have fallen out of love.
How Does Your Brain Influece Self-Control And Risk Of Cheating?
For individuals vulnerable to addiction, falling in love can be a tricky business. The intoxicating neurochemicals of love have drug-like effects. Recent research on love and addiction shows that brain scans reveal both romantic love and drugs activate the brain’s reward pathway.
The rush of dopamine makes you want to see the person you care about all the time. You crave their presence and attention, which drives you to find them. The “wanting” loop is the same circuitry found in substance abuse.
Related: 9 Natural Ways to Balance Dopamine in the Brain
Hence, the withdrawal from the chemicals of infatuation can drive some individuals to look for other sex partners to try to re-create that high.
But that’s not the only brain-based factor that can drive infidelity.
Problems in the brain’s self-control network can also lead a person to cheat on their significant other. The self-control circuit balances different parts of the brain. The deep limbic system pushes you to seek pleasure. Meanwhile, the prefrontal cortex (PFC) helps you think twice before risky actions, like having an affair.
When the self-control circuit is balanced, it gives you adequate impulse control to stop you from having an affair with a coworker or with your significant other’s best friend. However, when the PFC is low in activity, it can create an imbalance that causes you to give in to your impulsive desires without thinking about the consequences.
Interestingly, low activity in the PFC is a hallmark feature of ADD/ADHD. A survey of 3,000 individuals with ADHD found that 39 percent of men and 40 percent of women with this condition had at least one physical affair – much higher numbers than in the general population.
The hormone testosterone might affect how likely a man is to look for a sexual partner outside his relationship. A 2019 study found that men with high testosterone levels were more likely to have extramarital affairs than men with lower levels.
Testosterone is involved in mood, motivation, and sexuality. High testosterone levels are linked to lower empathy and a strong sex drive. This combination may lead to having an affair. The negative results can include divorce, losing half your money, and seeing your children every other weekend.
Why Do People Cheat? Psychological Motivations Behind Infidelity
Of course, cheating is not all about brain biology; there are other psychological factors at play. A recent study in the Journal of Sex Research looked at why nearly 500 young adults cheat. These adults admitted to being unfaithful while in a committed relationship.
The researchers identified eight common reasons people cheat:
- Anger – They admitted to seeking revenge for a partner’s betrayal.
- Sexual desire – They reported feeling unsatisfied with the sex in a relationship and wanting to explore something novel.
- Lack of love – They no longer felt passion or interest in a partner; fell “out of love.”
- Neglect – They were not receiving enough love, respect, and/or attention.
- Low commitment – One partner was not as committed as the other, or both partners didn’t have an understanding that their relationship was exclusive.
- Situation – They found themselves in scenarios outside the norm, such as being intoxicated, on vacation, or under high stress.
- Esteem – They were seeking to boost self-worth by having sex with multiple partners.
- Variety – They wanted to experience sex with as many partners as possible.
The survey responses also provided a number of insights about infidelity. Here are some of the highlights:
- Men and women have different motives for cheating.
Men were more likely to say they cheated for physical reasons. These reasons included sexual desire, wanting variety, and certain situations. On the other hand, women were more likely to cheat for emotional reasons, and mainly because of neglect.
- Motive impacts duration of infidelity.
People who cheated because of anger, revenge, lack of love, or a desire for variety had longer affairs. In contrast, affairs that happened due to situational infidelity, like being drunk or overwhelmed, ended sooner. Women tended to have longer affairs than men on average.
- Secrecy
By nature, infidelity is secretive. That said, some cheaters were less careful than others—and maybe intentionally so.
People who cheated due to a lack of love or low self-esteem were more likely to go on public dates. They also showed more public displays of affection toward their partner. To the contrary, situational cheaters were more private, which may be because they hoped to keep their primary relationship and not get caught.
- Emotional intimacy
When cheaters felt less connected to their main partner, they felt more emotional closeness in the affair. This may show that they were trying to meet that need. When lack of love was the motivation, individuals found the experience more intellectually and emotionally satisfying as well.
Ultimately, the survey showed that infidelity is complex and unpredictable. When infidelity arose from anger, lack of love, low commitment, or neglect, it was more likely to end. It was less likely to end when the infidelity was circumstantial. The varying motivations associated with infidelity indicate it can happen to anyone – even among individuals in seemingly contented relationships.
Individual & Personality Factors That Increase Cheating Risk
An individual’s past actions, personality traits, attachment style, and genetics can also increase the risk of infidelity.
Past infidelity increases the risk of future infidelity, according to a longitudinal study. The study found that people who cheated in their first relationship were three times more likely to cheat again. This was compared to those who did not cheat in their first relationship.
An individual’s personality type and attachment style can indicate a higher risk of infidelity. For example, people who cheat in romantic relationships tend to score higher in neuroticism. This means they may feel more anxious, unstable, and moody. They also score higher in openness to experience and extraversion. However, they score lower in conscientiousness. studies show.
Individuals who have subclinical levels of psychopathy, narcissism, and Machiavellianism – called Dark Triad traits – are well-known to have higher risk of infidelity. Research indicates that people with insecure attachment styles are more likely to cheat in marriages. This is especially true for those who are very anxious or avoidant.
Incredibly, there appears to be a potential genetic link to infidelity in some individuals. Researchers found that differences in dopamine signaling may make cheating more likely. This is especially true for people with lower dopamine levels. Specifically, research links genetic differences in dopamine receptor D4 to infidelity and unfaithfulness. It’s possible that this genetic makeup magnifies the brain’s response to novel and exciting experiences, making cheating more compelling.
How Do Relationship Problems And Life Stressors Influence Infidelity?
Even though many factors contribute to infidelity, one cannot overlook the role of the relationship itself. Longitudinal research shows that decreased satisfaction in a present relationship is closely related to infidelity among married people.
There are a host of factors that lead to relationship dissatisfaction. Psychologist John Gottman, cofounder of the Gottman Institute, studied marriage. He found that one of the worst things in a marriage is when a person ignores their partner’s attempt to connect. (A bid is any gesture, verbal or nonverbal, that asks for your partner’s support, affection, or attention.)
Rejected bids can cause emotional neglect, little to no effective communication, and sexual dissatisfaction, ultimately making infidelity more likely to happen.
Big stressors, like losing a job, money problems, illness, or caring for aging parents, can affect how we feel. Life changes, such as moving, starting a new job, or becoming a parent, can also play a role.
These factors can lead to more conflict in relationships. People may seek understanding and affection outside their relationships when this happens. Of course, stress also impairs self-control, which raises the odds of turning to an outside partner.
Substance abuse harms relationships. It breaks trust through lies and secrecy. It also replaces emotional closeness with selfishness and neglect. It promotes infidelity by lowering inhibitions and judgment, making risky behaviors like cheating more probable.
Being close to coworkers can lead to emotional or sexual affairs. This can happen when you interact with them often, either in the office or during business trips. This also applies to virtual contact through social media and dating apps.
How Can Couples Begin To Heal?
Infidelity causes many emotions in both the cheater and the betrayed. These feelings include anger, sadness, loss, anxiety, and depression. It can also lead to low self-esteem and sometimes PTSD. The emotions can be overwhelming.
To reduce blame and encourage healing, it is important to understand why a person cheats. This includes looking at their brain motivations, personality traits, attachment styles, and relationship dynamics. Addressing these underlying factors that contribute to infidelity is an essential part of healing.
Couples therapy can provide a safe place to express difficult feelings and begin to address underlying issues. With help and guidance, two willing partners can grow closer again by becoming more aware of patterns, learning to communicate needs, and taking care of brain issues. Slowly, over time, they can rebuild trust together.
FAQ About Brain Health and Infedelity
1. Do people cheat because they are “wired” to?
No, but brain biology can play a role. For example, some individuals have brains with low activity in the prefrontal cortex, which can impair their ability to control impulses and make sound judgments, increasing cheating risk.
Or the feel-good neurochemicals released with new love can be like a drug for some individuals, motivating them to seek the excitement and novelty of a new partner in order to feel that euphoria again.
2. Can brain chemistry alone cause cheating?
No. There are many factors that lead to infidelity. Brain chemistry is one of them.
3. Is it always betrayal of love, or just sex?
In some cases, it is about sex. Numerous studies indicate that men are more likely than women to cheat for purely sexual reasons or opportunism.
But more often, for both men and women, cheating results from a combination of factors including brain function, personality traits, and relational issues (emotional neglect, poor communication, resentment, etc.), to name a few.
4. Can Amen Clinics help uncover brain-related factors that may contribute to cheating?
Yes, Amen Clinics uses brain SPECT imaging and detailed clinical evaluations to identify patterns of brain activity that may increase vulnerability to cheating, such as low prefrontal cortex activity (linked to impulsivity), overactive emotional centers, or brain patterns associated with addiction-like behaviors.
By understanding how a person’s brain functions, clinicians can create a personalized plan to strengthen impulse control, improve emotional regulation, and support healthier relationship choices.
Infidelity, hormonal imbalances, relationship problems, and related mental health conditions can’t wait. At Amen Clinics, we provide personalized, science-backed treatment plans designed to target the root causes of your symptoms. Our 360-approach includes brain SPECT imaging, clinical evaluations, innovative therapeutic techniques, medications (when necessary), and holistic lifestyle recommendations to promote the health of your brain, body, and mind. Speak to a specialist today at 888-288-9834 or visit our contact page here.
Amen Clinics
Founded in 1989 by double-board certified psychiatrist and neuroscientist Daniel G. Amen, MD, Amen Clinics Inc. (ACI) is known as the best brain and mental health company in the world. Our clinical staff includes over 50 healthcare specialists, including adult and child psychiatrists, integrative (functional) medicine physicians, naturopaths, addiction specialists, forensic psychiatrists, geriatric psychiatrists, nutritionists, licensed therapists, and more. Our clinicians have all been hand-selected and personally trained by Dr. Amen, whose mission is to end mental illness by creating a revolution in brain health. Over the last 35-plus years, ACI has built the world’s largest database of functional brain scans—over 250,000 SPECT scans on patients from 155 countries—related to how people think, feel, and behave.
References
- Institute of Family Studies website
- “Who Cheats More? The Demographics of Infidelity In America”
- https://ifstudies.org/blog/who-cheats-more-the-demographics-of-cheating-in-americaAccessed 11/23/25
- Esch T, Stefano GB. The neurobiology of love and addiction: Central nervous system signaling and energy metabolism. Cogn Affect Behav Neurosci. 2025 Oct;25(5):1225-1236.
- Emotional Affair website“Is it possible that adult ADHD contributed to an affair?”
- https://www.emotionalaffair.org/adhd-contributed-to-an-affair/Accessed 11/23/25
- Klimas C, Ehlert U, Lacker TJ, Waldvogel P, Walther A. Higher testosterone levels are associated with unfaithful behavior in men. Biol Psychol. 2019 Sep;146:107730.
- University of Maryland website“Why do people cheat? UMD research identifies 8 motivating factors.” https://bsos.umd.edu/featured-content/why-do-people-cheat-umd-research-identifies-8-motivating-factorsAccessed 11/23/28
- Knopp K, Scott S, Ritchie L, Rhoades GK, Markman HJ, Stanley SM. Once a Cheater, Always a Cheater? Serial Infidelity Across Subsequent Relationships. Arch Sex Behav. 2017 Nov;46(8):2301-2311.
- C.J.J. van Zyl, et al. The five factor model and infidelity: Beyond the broad domains. Personality and Individual Differences.Volume 172, 2021. 110553, ISSN 0191-8869.
- Ghiasi N, Rasoal D, Haseli A, Feli R. The interplay of attachment styles and marital infidelity: A systematic review and meta-analysis. Heliyon. 2023 Dec 3;10(1):e23261.
- Garcia JR, MacKillop J, Aller EL, Merriwether AM, Wilson DS, Lum JK. Associations between dopamine D4 receptor gene variation with both infidelity and sexual promiscuity. PLoS One. 2010 Nov 30;5(11):e14162.
- Previti, D., & Amato, P. R. (2004). Is Infidelity a Cause or a Consequence of Poor Marital Quality? Journal of Social and Personal Relationships, 21(2), 217-230.
- The Gottman Institute website
- “How do affairs happen?”
- https://www.gottman.com/blog/how-do-affairs-happen/
- Accessed 11/23/25
