Why You Were Smart Not to Take that Cheating Jerk Back

"Once a cheater, always a cheater" is the classic saying. But is there any validity to the assumption that one small instance of infidelity is a sign of a lifelong pattern?

In short, yes — if you're dating someone with a wandering eye, there's scientific evidence that past cheating may indicate they'll do it again. 

But what matters most is whether the person really was a serial cheater, or if the affair was about something else. Figuring out why someone cheated can be the answer to unlocking what's really going on in your relationship.

Bad habits die hard: A study of unmarried 18- to 34-year-olds conducted in 2014 at the University of Denver found that people who cheat in one relationship are three-and-a-half times more likely to cheat in the next one. 

This is in line with previous research, including a 1999 study of college students published in the Journal of Social and Personal Relationships that found that 86% of the men and 62% of the women had done it more than once. The likelihood for repeating held across the board for all kinds of cheating: kissing, oral sex, sex. Cheating behaviors were associated with the participants' beliefs in sex and marriage, a game-playing mindset and their self-perceived ability to deceive their partner. 

In other words, these were people with cheating-inclined attitudes. So once the gates of two-timing open, they're bound to stay open.

The motives matter: But, as sex researcher Justin Lehmiller points out, the likelihood that someone is a cheater for life is actually determined by why they cheated: "Did the reason for cheating stem from something specific to that relationship, or something specific to that individual?" he asks. 

For serial cheaters, the reason is specific to the individual. Serial cheaters share key common traits: Researchers have found that people who engage in "regretful sexual behavior" when they're distressed or enter relationships with low compatibility are often cheaters. In 2004, a study from Bradley University examined major personality traits and found that low agreeableness and low conscientiousness, or people who display less caring and self-aware behavior, were closely linked to infidelity. 

But cheating is often specific to the relationship, making it more likely a one-time discretion. Studies have indicated that relationship dissatisfaction, whether it's a personality mismatch, external stress or even sexual problems, is one of the top reasons why people cheat. If the reason someone cheated is purely situational to that one terrible relationship, then it doesn't mean they're prone to cheating for life. It's not always a case of good vs. evil, as the tabloids like to spin it.

Getting to the bottom of it: That's the meaningful takeaway from the most recent episode of WNYC's Death, Sex, and Money podcast: Cheating often isn't about someone being a serial cheater but about fundamental problems in a relationship.

WNYC's Anna Sale found that cheating comes in countless forms and for a variety of "mundane" reasons, from boredom to feeling ignored. Because the causes are nuanced, there's no one right way to respond (breaking up, staying together, opening the relationship). Cheating can serve as a mature moment to reassess. "When a secret affair is revealed, it's a moment for us to finally and fully be honest about what was missing from a relationship, and what's worth saving," Sale said. 

Besides, cheating may be the most ubiquitous relationship problem of all. While studies flip-flop on the exact number, a conservative estimate made in 2007 based on multiple samples is that cheating occurs for up to 25% of heterosexual married couples. And it comes in many forms. As author and advice columnist Cheryl Strayed wrote in her "Dear Sugar" column:

 "Painful as it is, there's nothing more common in long-term relationships than infidelity in its various versions (cheated, pretty much cheated, cheated a teeny bit but it probably doesn't quite count, came extremely close to cheating, want to cheat, wondering about what it would be like to cheat, is flirting over email technically even cheating? etc)."

All of our small doubts, questions and indiscretions are often the result not of malicious intent but rather weakness and unhappiness. Getting to the bottom of that can be incredibly positive. As Strayed found after she caught her husband cheating, "I'm grateful it happened."

That said, a serial cheater is a serial cheater. Sometimes the cheating isn't about the relationship but about the person being a jerk — in which case, it's an excellent decision not to take them back. It all hinges on the question: Why did they cheat? The answer to that question, not the cheating itself, could determine the future of your relationship.