Why People Cheat: The Neuroscience of Infidelity

Why People Cheat: The Neuroscience of Infidelity


Do you remember when the news broke that Tiger Woods had cheated on his wife Elin Nordegren? When actress Kristin Stewart was accused of being unfaithful to her Twilight costar Robert Pattinson? Or when Jay-Z admitted to stepping out on his wife Beyoncé? Or the countless Kardashian love triangles?

Celebrities aren’t the only ones being unfaithful to their significant others. Statistics show that 20% of married men and 13% of married women admit they’ve engaged in sexual activity with someone outside their marriage. Infidelity rises as people age. More women cheat in their 60s (16%) than at any other time of their life. The highest rate of infidelity among men is seen in those in their 70s, with 26% of men in this age group having sex outside marriage. It’s no surprise that infidelity often leads to marital conflict, divorce, and broken families.

Have you ever wondered what makes some people cheat on their significant other? It all lies in the brain. Here are 4 brain-based reasons why some people stray, but before jumping into these reasons, it’s important to get to know the neurochemicals involved in the process of falling in love.

The Neurochemicals of Love and Lust

Mother Nature formulated a very powerful concoction when she created the potion of chemicals involved with infatuation. Romantic love and infatuation are not so much an emotion as they are motivational drives. They are part of the brain’s reward system. These feelings intensify to 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). Let’s take a closer look at these chemicals.

  • Epinephrine causes an adrenaline rush that makes your heart beat faster, your blood pressure rise, and your breathing quicken.
  • Dopamine is associated with pleasure, motivation, and concentration. It has been shown to work in the reward centers of the brain. High levels of dopamine are associated with attraction and feeling sexy.
  • Serotonin is known as the feel-good neurotransmitter, and it drops dramatically during periods of new love. This is linked to the obsessiveness people tend to feel when they can’t stop thinking about their new partner.
  • PEA is an adrenaline-like substance that speeds up the flow of information between nerve cells and is triggered in the process of attraction to help us pay attention to the love feelings. PEA is known as the “love molecule” because it is what initiates the flood of chemicals into the brain along with norepinephrine and dopamine to create the feelings of euphoria and infatuation when we are highly attracted to someone.

1. When New Love Fades—Getting Addicted to Infatuation

For those of us who have had the wonderful experience of falling in love and being infatuated with someone, we also know that this amazing high and trance-like bliss does not last forever. We either progress into deeper love and commitment or make the decision to break apart and detach.

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.

Many couples therapists note that a lot of unnecessary divorces and relationship breakups can occur during this time because people mistake the lack of intensity and euphoria as a sign that they have fallen out of love.

For some people, the withdrawal from the chemicals of infatuation can drive them to look for other sex partners to try to re-create that high. This is similar to the process seen in substance abuse. In some individuals, the need to feel that rush of new love keeps them seeking out extramarital affairs.

2. When Self-Control Short-Circuits

Problems in the brain’s self-control network can also lead a person to cheat on their significant other. The self-control circuit is a sort of balancing act between brain regions (deep limbic system) that motivate you to seek out pleasurable activities and other regions (prefrontal cortex) that make you think twice before engaging in risky behavior, such as extramarital affairs.

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 prefrontal cortex (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.

Brain imaging studies show that people with low activity in the PFC are more likely to get divorced. Low activity in the PFC is a hallmark of ADD/ADHD, and a survey found that 39% of men and 40% of women with this condition had at least one physical affair—much higher numbers than in the general population.

3. The Testosterone Factor

The neurohormone testosterone may also have something to do with a man’s likelihood of seeking a sexual partner outside a 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 associated with lower empathy and a high sex drive, which could be the prescription for having an affair, getting divorced, losing half your net worth, and visiting your children every other weekend.

4. Unfaithful Brains are Different

Brain imaging studies have found that the brains of men who are monogamous differ from those of men who cheat. A 2017 study found that when men looked at romantic images—couples holding hands or gazing into each other’s eyes, for example—brain activation differed between the faithful and unfaithful ones. The research indicated that monogamous men showed more reward-related neural activity when viewing romantic pictures compared to non-monogamous men.

If you want to stay in a committed relationship, it’s a good idea to enhance your overall brain health, strengthen your PFC (think lots of physical exercise, green tea, and rhodiola), and optimize your hormone levels. It could help you and your partner stay faithful to each other.

At Amen Clinics, we take a unique brain-body approach to diagnosis and treatment that includes brain SPECT imaging, as well as laboratory testing to check physical health, and other important factors that could be contributing to bad behavior. By getting to the root cause of your unwanted behaviors, we can create a more effective, personalized treatment plan for you.

If you want to join the tens of thousands of people who have already enhanced their brain health, overcome their symptoms, and improved their quality of life at Amen Clinics, speak to a specialist today at 888-288-9834. If all our specialists are busy helping others, you can also schedule a time to talk.



  1. My wife & I were facilitators in the program Dynamic Marriage (marriagedynamics.com); which has a success rate average of over 80+% to renew marriages, but most often make the marriage better than it ever was and not uncommon to make a marriage better than they ever knew it could be. What we saw time after time was the major cause of marriage failing, having an affair or just being numb, unpleasant was you had two people living in the same house living two separate lives. The cure was each spouse defining their top three emotional needs (which they have never done), sharing those needs and defining which ones they will do together or separately. The ones they decide to do together take priority over the ones they decide to do separately. What I’ve also found is if the emotional needs aren’t being met there almost always “someone” who is more than willing to meet those needs, FOR A TIME, and you end up with an affair (been there!). As Dave Carder in his book “Torn Assunder” (FANTASTIC BOOK) says way over 90% of people ending up in affair was never looking for an affair.

    Also, read the chapter on “Limerance” in Joe Beam’s book “Your Love Path” or I can send it to you. Basically, it takes 6 months to 3 years before our “rose colored glasses” fall off and we see the real other person we are infatuated with and all of a sudden we are at the point of “who is this person” who’s relation with has already done serious damage. Read his “Limerance” chapter – AN EYE OPENER!!

    Comment by David Chance — July 17, 2020 @ 6:02 AM

  2. Completely agree with commentor David Chance.People cheat because their emotional needs are not met, men and women. And I have a few issues with this article.
    1. I must doubt your stats saying that older married people are more likely to cheat. Particularly for men, because when they get older their testosterone levels decrease while their estrogen levels increase so they focus more on their marriage bond and gain greater awareness of feelings, especially to their wives. And if they have been married long and are relatively satisfied with their marriage, at this point in life they are not enticed by the idea of adultery. For women, I can understand she wants out especially when she endured an abusive marriage, however, she is more likely to just divorce/separate to get away from it all instead of choosing adultery. For her, at this point in life, she is more likely to think about the negative consequences to her own livelihood and affected family members, which most likely will immediately stop her immoral thoughts and trajectory. Furthermore, don’t we see the younger ages 20-50 divorcing and hearing of their infidelity?
    2. Furthermore, there are more factors. Like faith, attachment styles, family history, how committed they are to safeguarding their marriage, environment, and personality bents that also predict how faithful someone is. This article makes it so simplistic and that’s it’s only about the brain, and that people can’t control their brain makeup, but there’s actually many factors involved.

    Comment by Elizabeth Chang — July 17, 2020 @ 4:15 PM

  3. I wouldn’t discount brain damage or injury from an accident either. When you look at the erratic behavior off-the-field by football players, it’s likely front lobe damage to the brain that comes with lack of common sense or good decision making.

    Without that, many of these guys go offtrack, sometimes in very bad ways as we’ve seen over the years. A good relationship needs both people to engage with balance and common sense. But it sure won’t take long for thinga to unwind if one partner’s not able to function properly.

    Then you’ve also got sociopaths whose primary goals are total ppwer and control over others. I would bet there might be more than a few examples you’ve seen and experienced in your years of work, Dr Amen!

    Would love to hear some of those stories!

    Without naming names, of course. 🙂

    Comment by Robert L — July 17, 2020 @ 8:14 PM

  4. Hi – I suffered 2 concussions within 3 weeks in 2016. I didn’t rest properly because I was having needed repairs done to my condo. In 2018 moved to a 55+ retirement community and the headaches returned when my street needed repairs this spring. My primary care said I have chronic concussion and tension headaches and wants to put me on an antidepressant. I don’t like drugs because of the unwelcome side effects. I’m trying deep breathing exercises and avoiding stress as much as possible. I do see a little improvement now that the noise from the repairs has subsided but it is a daily struggle to keep the headaches at bay. Will I ever get rid of them completely and what can I do further to treat them?

    Comment by Diane — July 18, 2020 @ 8:30 AM

  5. Hi Diane,
    I just happened upon this article today and I saw your comment. Back in 2010 we took our daughter to the AMEN Clinic. She was 12 at the time. She was struggling in school and her teacher mentioned that she might have ADD. I wanted to get a more comprehensive testing done instead of regular district accademic testing or psychological testing. The brain scan was very enlightening. Unfortunately, at the time we were so focused on her being able to start the school year more focused we put her on ADD medication. After a couple of weeks she did not like how she was feeling on them. Recently when I was reviewing her brain scan info I noticed that Neurofeedback was highlighted in yellow. In 2010 not much was in public awareness about Neurofeedback. The Neurofeedback field is finally starting to be recognized for its benefits. I started to have Neurofeedback sessions for myself. The type of Neurofeedback that I am doing is called LENS. While reading a book about LENS Neurofeedback a lot of research has been done on it’s positive affects on Traumatic Brain Injuries(TBI) as well as headaches. I felt inspired to share with you this modality. I really wish that I had taken the AMEN clinic advice back in 2010 and took my daughter to a Neurofeedback practitioner. I feel the trajectory of her life would have been so different. I am noticing huge shifts and benefits in myself just after a couple of months doing weekly sessions. Best of wishes to you as you find relief from your daily struggles.

    Comment by Linda Yuncker — July 29, 2020 @ 11:02 AM

  6. "I was with a girlfriend for five years and was making plans to propose to her. Then one day, she said she wanted to take a break to figure things out. That was about four years ago. She got married about two years after her "break" to a coworker who I later found out through the help of hackgoodnesstech on insta, gram that she had been cheating on me with the whole time we were together. I was devastated at the time, but now I think it was all for the best. Also, it's a small world, because her husband is cheating on her with my staff. Thanks karma!" I might just give my staff a promotion, what do you guys think?

    Comment by William Stone — July 7, 2022 @ 11:34 AM

  7. My husband had metastatic brain cancer. We verly rarely had sex and he said it was because he didn't feel well . I found out 2 days after his memorial service that he had been cheating on me with his ex-wife for at least 3 years before he died. I wonder if the brain cancer made him impulsive, or even sorry for hurting her in the past. Needless to say, I am devastated, and trying to make sense of this.

    Comment by Deborah Claybrook — December 6, 2022 @ 3:33 PM

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