From the article: A new study published in the Archives of Sexual Behavior reveals the relationship between jealousy, the gender of both the partner and their rival, and the type of infidelity (sexual vs. emotional). The study included a large group of individuals identifying as heterosexual, bisexual, or homosexual.

The research found that individuals were consistently most jealous of rivals that were of their own gender, except in the case of bisexual women. Bisexual women were most jealous when their female partners were involved with men. The research team states, “jealousy was influenced by sex and sexual orientation of the individuals, sex of the partners, and also by sex of the rivals: same-sex rivals were perceived as most threatening.”

Prior research on the origins of jealousy had found that jealousy was often highest when there was a “reproductive risk.” In other words, if the partner was at risk of becoming pregnant, the jealousy was more intense than what would be found in other scenarios.

Heterosexual men have been shown to be the only group more concerned about sexual affairs than emotional ones. It appears that in heterosexual relationships, from the male perspective, the reproductive risk their partner takes if they are sexually unfaithful triggers feelings of jealousy.

Study author Jaroslava Varella Valentova and colleagues sought to explore the complexities of diverse romantic pairs, the various potential rivals, and the different types of infidelity (sexual or emotional). As stated by the research team, the goals were to investigate “the possible effects of sex and sexual orientation of the individual, and sex of the partner and rival on reported sexual versus emotional jealousy.”