Issues of fidelity—and infidelity—come up all the time in romance novels. Often issues of trust between characters hinge on past experiences of cheating. The key for writers is to show suspicion and distrust—or trust and confidence—in a credible way.
Imagine that on the way home from a party, your spouse says to you, “Something’s wrong there—I think X is cheating on Y.” Could this statement be true? Can you tell if people are cheating just by watching them, even for a few minutes?
The answer’s yes. Psychologists at Brigham Young University examined whether observers could identify people who cheat. Results suggest that signs of infidelity can emerge in as few as three to five minutes, and that random observers are remarkably consistent and accurate in their observations.
In the first study, one member of each couple completed a survey about the relationship, including whether they had been emotionally or physically unfaithful. Then the couples were asked to complete a small task, lasting three to five minutes, that required them to work together. Observers watched the activity sessions and then ranked on a one-to-five scale their answers to questions such as: “How likely is it that this person flirted or made advances on someone other than the partner?” and “How likely do you think this person has had sexual intercourse with someone other than his/her partner?”
The researchers found a “significant and moderate” correlation between the observers’ assessments of the likelihood of infidelity and the participant’s self-described actual infidelity.
In a second study, the observers also assessed how trustworthy and committed each participant was to the relationship. They again identified cheaters, essentially by picking up on verbal or visual clues that pointed to ambivalence or unreliability, which cast doubt on the subject’s fidelity.
So if you’re writing about a jealous partner, a wronged spouse, or a suspicious friend—you can take that suspicion and run with it. Maybe your characters are just suspicious and cynical. On the other hand, their observations—however painful—are probably correct.