Jealousy promotes relationship maintenance by reducing partners’ extra-pair liaisons. On average, men report higher distress about their partner’s sexual infidelity, while women show higher emotional jealousy. These sex differences are specific to heterosexuals, and to contexts with potential reproductive costs. Here we tested the effect of sex and sexual orientation of the individual, sex of the partner and of a potential rival on sexual versus emotional jealousy. In total, 416 heterosexual, homosexual and bisexual men and 1328 women from Brazil, Chile and Portugal responded the Sexual vs Emotional Jealousy Scale, and they ranked distress of four imaginative scenarios: sexual or emotional relationship of the partner with a male or a female rival. To test for effect of partners’ sex, bisexual individuals responded twice, about a female and about a male partner. Heterosexual men reported higher sexual jealousy than the other groups. Individuals were most preoccupied with their partner's emotional relationship with rival of the same sex as the respondent. Compared to other groups, heterosexual men and women were the most preoccupied with sexual infidelity. Bisexual individuals did not show any systematic differences in their jealousy type with respect to the sex of their imagined partner. Thus, jealousy is not influenced only by sex and sexual orientation of the individuals, but also by sex of the rivals: same-sex rivals are perceived as the biggest threat. Besides being a strategy to maintain a primary relationship, jealousy can also be a specific intrasexual competition strategy.