Cheating on someone, or being cheated on (read more about infidelity here), represents one of the more traumatic events that can occur in any romantic relationship. Although the reported incidence rate of infidelity varies considerably by sample and relationship type, suffice it to say that affairs are not uncommon in marital and non-marital relationships. And people (in those relationships) suspect it’s common – when asked, people generally presume that people cheat frequently (hence the prevalence of tabloid magazine lists on ‘how to spot a cheater’).

Yet, despite the apparent widespread presumption that staying true to another is no easy task, people likewise presume their own partners are highly unlikely to stray. A number of studies, mostly focused on married individuals, have documented a clear gap between the frequency of infidelity (i.e., people admitting they have cheated on their spouses) and individuals’ expectations that their partner has cheated. Basically, people believe others cheat, and even report doing it, but still don’t tend to think it has happened, or will happen, in their relationships.

In a recent study published in the Journal of Social and Personal Relationships, researchers identified daters’ (vs. married spouses) thoughts about the frequency of cheating in their own and others’ relationships. The researchers also wanted to see how well individuals’ expectations about what happens in their relationship might map on to reality. They surveyed nearly 200 individuals, ages 17-32 (89 males; 108 females), who had been dating their partners an average of about 22 months. Most indicated they were in an exclusive relationship…but were they? – keep reading!

As part of a larger study, all participants were asked a series of questions about infidelity in their own and others’ relationships so the researchers could compare what daters think happens in their own vs. others’ relationships. Here are some of the key findings:

Not surprisingly, almost all the daters indicated that it is very important their partners don’t cheat on them.

As such, most participants (more than 9 out of every 10) said they’d want to know if their partner has ever or does cheat on them.

Yet, despite how much people care about infidelity, the majority of participants (roughly 7 out of every 10) indicated that they had not had an explicit conversation with their partner about what “counts” as cheating or what they expect from their partners in the fidelity department.

Summary: People care a lot about (in)fidelity, but aren’t likely to discuss it with their partners. You may be thinking “Why would they discuss such things when of course everyone knows you’re not supposed to cheat?” Never mind the fact that there’s an enormous amount of variation in what constitutes cheating, but it gets more interesting:

These very same participants guesstimated that the average person of the opposite sex (in a similar type of dating relationship) has a roughly 40% chance of ever cheating on a romantic partner.

And about 9% of the study participants reported having actually cheated on their own partner at some point in the past.

cheated on their own partner at some point in the past. But when asked directly, only 5% of participants believed that their own partner had cheated or will cheat at some point in the relationship.

In other words, daters in this study were unlikely to talk about infidelity with their partners but, at the same time, presumed that the likelihood of cheating in the general population was fairly high. And they reported actually cheating at twice the rate than they thought their own partners would cheat. Add this pattern of results to the lowest published rate of infidelity in dating relationships — 14% — and it becomes pretty clear that folks are engaging in some fairly (risky) wishful thinking.

Do these results mean that people should be walking around looking for cues that their partner is a philanderer? Not at all. But the findings do highlight the degree to which people are motivated to really want to believe their relationships and partner is better than others. And that wishful thinking may blind individuals to real warning signs.

Watkins, S. J., & Boon S. D. (2016). Expectations regarding partner fidelity in dating relationships. Journal of Social and Personal Relationships, 33, 237-256.