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Serial Cheater Psychology: The 3 Personality Types Most Likely To Cheat

Carmen McGuinness, EdD, BCBA-D
Updated on January 22, 2021
Carmen McGuinness, EdD, BCBA-D
Board-Certified Behavior Analyst
By Carmen McGuinness, EdD, BCBA-D
Board-Certified Behavior Analyst
Carmen McGuinness is a board-certified behavior analyst, acceptance and commitment therapist, and the author of three popular academic books for families.
January 22, 2021
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In Gallup polls, 91% of people say infidelity in a marital partnership is morally wrong, and 64% say they would not be prepared to forgive their partner if caught cheating. And yet, 54% of Americans say they know someone who has an unfaithful spouse.

Research in the field of infidelity reveals that there are three distinct personality types correlated with a higher likelihood of cheating: sociopaths, narcissists, and lonely hearts.


Sociopaths and psychopaths

Psychopathy is the tendency to disregard the moral code and the rights of others, acting purely on one's own behalf. Experts disagree about whether or not the distinctions between psychopathy and sociopathy are significant enough that the terms can't be used interchangeably. In broad terms, psychopathy is considered a more severe form of sociopathy. All psychopaths are sociopaths, but not all sociopaths are psychopaths.

That said, the traits shared by psychopaths and sociopaths are the traits that make both types more likely to cheat: a disregard for social mores and the rights and feelings of others, and a failure to feel remorse or guilt.

Psychopathy has a strong correlation to infidelity1, with a very high likelihood that a psychopath or sociopath will engage with other sex partners outside the marital relationship. Psychopaths also tend to have a higher number of lifetime sex partners. They are better able to separate love from sexual activity, and they are more willing to engage in behaviors involved in an unfaithful relationship or lifestyle, like prolonged periods of lying2.



In contrast, narcissism is hallmarked by grandiosity and conceit. The narcissist believes they are better-looking, smarter, fitter, and more worthy than their spouse, which leads them to believe they are entitled to cheat3. And that they believe they are better-looking, smarter, fitter, and more worthy than their affair partner may lead them to believe they are entitled to use them exclusively for their own sexual pleasure. (Sexual narcissism itself can be considered one specific type of narcissism.)

Interestingly, though they may get up to the same unsavory social behaviors, sociopaths and narcissists are two very different fellows. That handsome narcissist across the coffee bar is likely to be somewhat neurotic, with a deep underlying lack of confidence, stemming from an insecure attachment to the primary caregiver in early childhood. Under their confident exterior, they may secretly suffer from excessive worry, guilt, and anxiety.

Meanwhile, the smooth-operating and deceitful sociopath two seats over is much more detached, resulting from an avoidant attachment to his primary caregiver, if they had one. People with an avoidant attachment style have trouble getting close to, trusting, and relying on others. They actually seek out relationships that are more likely to be distant and less emotionally demanding. Their early bonding experience likely involved a distracted or dismissive authoritarian parent who failed to satisfy their needs. As a result, they seek comfort from those who are less intimate and committed in their relationships. And an extramarital relationship perfectly avoids the threat of intimacy in a sexual relationship, which explains the link between attachment avoidance and infidelity.

Meanwhile, the narcissist may actually crave and long for the intimacy that was lacking in their early attachment to their parent, and they may very well be lacking in their current relationship with their partner.

Studies show that both the sociopath and the narcissist tend to have more lenient attitudes toward infidelity4 than does the typical Gallup responder. They tend to be more permissive about sex, have a greater desire to have casual sex, and are more willing to engage in sex without emotional commitment. They tend to be dominant in their relationship with their spouses, have a higher propensity for sexual excitation (referring to how often and to what degree one becomes sexually excited), be sensation seekers (referring to both exciting and possibly dangerous situations), and score higher on psychological measures of impulsivity, or the inability to control one’s actions.

The marital relationships resulting from the early bonding patterns of sociopaths and narcissists tend to include poor problem-solving patterns, a lack of coping skills, little consistency, low mutual respect, and poor communication skills. In addition, satisfaction of time spent together, satisfaction with physical appearance, and social prestige are all lower in marriages containing either sociopaths or narcissists.


Lonely hearts

The lonely heart is a much broader and perhaps more interesting category.

Among one study of 100,000 subjects, boredom was the reason given for infidelity by 71% of unfaithful men. Additionally, people married to partners who are emotionally unavailable or have difficulty enjoying intimacy may find that their emotional needs can be met in an extra-marital affair. Not surprisingly, the data show that couples who have fewer and or less intense positive sexual interactions are at higher risk, as are those who report low sexual satisfaction. And in this case, contextual factors, such as having friends or family members who cheat, having access to valuable alternative sex partners, and watching porn may increase the likelihood that a lonely spouse will make the decision to engage in extra-marital sex.

That isn't to say that all lonely or sexually unsatisfied people will cheat, though: Communication skills (the way in which partners share information, thoughts, and emotions by verbal and non-verbal exchange) is one area of emotional availability that impacts the likelihood of an unfaithful liaison, and it correlates with a sense of belonging within the partnership structure.


It's easy to look at this list of traits and conclude that your cheating ex was an evil psychopath or that they cheated because you weren't having enough sex with them. Both of these things could be true, but it's important not to jump to conclusions. There are many reasons why people cheat, and it's not always because they're a terrible person at core.

Even when we use terms like "psychopath" and "narcissist" to describe people, it's important to remember that these characteristics actually exist on a spectrum—and the average person will have at least some level of narcissistic traits even without having a narcissistic personality disorder.

All that said, there are definitely some trends when it comes to the characteristics of a cheating partner that you can look out for before entering your next relationship.

Carmen McGuinness, EdD, BCBA-D author page.
Carmen McGuinness, EdD, BCBA-D
Board-Certified Behavior Analyst

Carmen McGuinness, EdD, BCBA-D, is a board-certified behavior analyst, acceptance and commitment therapist, and the author of three popular academic books for families, including Reading Reflex and How to Increase Your Child's Verbal Intelligence. McGuinness has a master's in Health Psychology and Behavioral Science and a doctoral degree in special education and behavior analysis from Nova Southeastern University.