Jealousy can be devastating to a relationship—and it is well known that the genders experience the green-eyed monster in different ways. Men are more likely to be jealous of sexual peccadilloes and women of emotional infidelity, according to past research. The oft-quoted evolutionary explanation is that men care more about sex because an unfaithful partner could mean raising someone else’s kids, whereas women are protective of emotional attachments because the biggest danger for them is being left alone with the burden of single parenthood. But a new study from Pennsylvania State University suggests it may be time to rethink why the genders respond differently to each indiscretion.

In a study of more than 400 people, clinical psychologists Kenneth Levy and Kristen Kelly found that individual personality differences—which stem from a person’s childhood experien­ces—explain the genders’ jealousy patterns. The pair asked subjects what would be more upsetting: their partner having sex with someone else or form­ing a strong emotional bond with an­other person. Both men and women with a kind of insecure attachment called dismissing—typical of people who had inconsistent or insensitive parents and learned to shun intimacy and become “hyperindependent”—were the most likely to report being jealous of sexual infidelity. More men than women have a dismissing at­tachment style. The reason for this gender difference is unclear but may relate, in part, to cultural notions of what constitutes “manly” behavior. Levy says this understanding of per­sonality formation, known as the at­tachment model, seems to explain both the average differences between men and women in what makes them most jealous, as well as the previously unexplained fact that a subset of indi­viduals better fits the jealousy profile of the opposite sex.