Will he cheat? Is she loyal? Recognizing signs of impending infidelity might be easy in hindsight—"I should have known!"—but in practice, it's hard to predict such acts before they happen.
Are there certain characteristics that make people more likely to cheat?
Consider sexual desire. Maybe an individual's strong urge for sex can help identify that he or she may be more likely to cheat—after all, we know that different people crave sex to different degrees. Are those of us who have exceptionally strong sex drives more likely to be unfaithful? Researchers aren't suggesting it's ever the only factor, but it could be an important predictor. A strong sexual desire may even be necessary to compel someone to engage in sexual behaviors outside of a committed relationship. But what about those individuals who feel an intense pull toward having an extra-dyadic affair but still resist? Or those who have a strong sex drive but have the discipline to channel that sexual energy toward their own partner?
This puzzle was tackled by McIntyre and colleagues (2014) in two empirical studies that unravel the relation between sexual desire and infidelity. They identified a powerful characteristic that could help explain when and why strong sexual desire only sometimes predicts infidelity: self-control.
Self-control refers to the ability to regulate impulses, such as caving in to a temptation. When people are low in self-control, it might be that their initial inclination toward sex becomes their default action: How intense their usual sexual desire is translates into behavior. If so, when low self-control is paired with high sexual desire, individuals might be more prone to flirting or engaging in sexual behaviors outside of a committed relationship. For individuals with low sexual desire, low self-control might orient them even less towards infidelity.
The first study reveals this is true: Researchers measured the self-control, sexual desire, and cheating histories of more than 300 individuals and found that stronger sexual desire predicted more past infidelity, but only for individuals who were also low in self-control (McIntyre et al., 2014).
Their second study involved experimentally reducing the self-control of a subset of participants through a laborious, detail-oriented drawing task. For the exercise, those with strong sexual desires and depleted self-control drew themselves sitting closer to an attractive stranger. Participants also responded to a hypothetical scenario in which they were in a committed relationship but met an attractive stranger. Those participants with strong sexual desires and low self-control indicated greater intention to engage in romantic behaviors with that stranger.
What does this mean? A strong sexual desire alone doesn't tell much about whether someone is more or less likely to cheat—the evidence points to individuals with strong sexual desires who resist the temptation. But if you add in the construct of self-control, the picture becomes a bit clearer: Depleted self-control might make it harder for individuals with strong sexual desire to resist, and allow people with low sexual desire to retreat further away from an extra-dyadic sexual encounter.
Much research on self-control (although debated in recent findings) suggests that self-control might be like a muscle, and as a muscle, it might become tired when overused. Think of the many scenarios that require self-control—doing chores, dieting, controlling emotions in social relationships at work or school, not speaking on impulse, completing undesirable tasks. If self-control can be depleted, couples might be mindful of how drained their partner is in terms of self-control before entering situations that involve interacting with attractive strangers.
Take note: Neither self-control nor sexual desire are the only factors involved in predicting infidelity. In fact, relationship dissatisfaction is one of the most powerful predictors (Whisman, Gordon, and Chatav, 2007). This underscores the idea that the quality of one's relationship is never to be ignored, even in light of personality (e.g., strong sexual desire) or situational experiences (e.g., self-control depletion) that could contribute to the likelihood of cheating.
McIntyre, J. C., Barlow, F. K., and Hayward, L. E. (2015). Stronger sexual desires only predict bold romantic intentions and reported infidelity when self‐control is low. Australian Journal of Psychology, 67, 178-186.
Whisman, M. A., Gordon, K. C., and Chatav, Y. (2007). Predicting sexual infidelity in a population-based sample of married individuals. Journal of Family Psychology, 21, 320-324.