Sex Q&A

Sex Question Friday: Is There Any Truth To “Once A Cheater, Always A Cheater?”

February 13, 2015 by Justin Lehmiller


A reader submitted the following question:

“Is it a bad idea to get involved with someone who I know cheated in their last relationship? I mean, once a cheater, always a cheater, right?”

You’re certainly not alone in thinking this. It is a very common belief that someone who cheats once is bound to do it over and over again; however, the reality is that not everyone who cheats is equally likely to repeat this behavior in the future.

Let me first say that research has indeed shown that cheating is often a recurring pattern of behavior. Consider this: in one study of college student dating relationships, researchers found that, among those who had previously had sexual intercourse outside of their primary relationship at least once before, 86% of men and 62% of women did it more than once [1]. Of course, keep in mind that this is just one study and it only looks at young people in dating relationships—the numbers would probably be quite a bit different in an older sample of married couples (the numbers would probably also differ depending upon how you define “cheating”). However, these numbers suggest that, when it comes to cheating, history often (but not invariably) repeats itself.

So what determines whether someone is likely to cheat again? It depends upon their reason for cheating in the first place. Specifically, did the reason for cheating stem from something specific to that relationship, or something specific to that individual?

Research has found that one of the most common reasons people cheat is because they are dissatisfied with their current relationship (e.g., perhaps they are extremely unhappy, they have emotional or sexual needs that are going unfulfilled, or the partners simply are not a good match) [2]. If a person who cheats for such as reason ends up in a future relationship that is more satisfying, it is not necessarily the case that they will cheat again. To put it another way, a situation-specific cause for cheating will not necessarily predict behavior in future relationships.

That said, research has also found that cheating is linked to a range of personality characteristics. For instance, two of the Big Five personality traits have shown consistent links to cheating. Specifically, people who are more agreeable (i.e., those who are kind and who care about other people’s feelings) and/or more conscientiousness (i.e., those who are dependable and have a lot of self-discipline) are less likely to cheat than people who have lower scores on these traits [3]. Likewise, our “sexual personalities” are associated with infidelity too. As one example of this, research has found that people who have a tendency to pursue regretful behaviors when they are stressed or anxious (perhaps as a means of psychological escape) are more likely to cheat [4]. To the extent that one has these personality characteristics or other psychological traits that increase susceptibility to infidelity (e.g., sensation seeking tendencies, narcissism), cheating is likely to recur regardless of the context of the relationship.

In short, there is definitely some truth to the old saying “once a cheater, always a cheater,” but it is not true in all cases. For some people, cheating is a one-time thing, whereas for others, it is a recurring pattern of behavior, with the key factor distinguishing these two cases being the underlying cause of infidelity.

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[1] Wiederman, M. W., & Hurd, C. (1999). Extradyadic involvement during dating. Journal of Social and Personal Relationships, 16(2), 265-274.

[2] 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.

[3] Schmitt, D. P. (2004). The Big Five related to risky sexual behaviour across 10 world regions: Differential personality associations of sexual promiscuity and relationship infidelity. European Journal of Personality, 18(4), 301-319.

[4] Mark, K. P., Janssen, E., & Milhausen, R. R. (2011). Infidelity in heterosexual couples: Demographic, interpersonal, and personality-related predictors of extradyadic sex. Archives of sexual behavior, 40(5), 971-982.

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Written by
Dr. Justin Lehmiller
Founder & Owner of Sex and Psychology

Dr. Justin Lehmiller is a social psychologist and Research Fellow at The Kinsey Institute. He runs the Sex and Psychology blog and podcast and is author of the popular book Tell Me What You Want. Dr. Lehmiller is an award-winning educator, and a prolific researcher who has published more than 50 academic works.

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