The goal of the present study was to examine the emotional content and intensity of jealousy in response to different types of infidelity (both online and offline unfaithful partner behaviors) among Dutch heterosexuals (n = 191) and homosexuals (n = 121). Based on previous research (Dijkstra, Barelds & Groothof, 2010), participants were presented with ten jealousy-evoking situations following which the intensity of two different emotional aspects of jealousy was assessed (betrayal/anger and threat). Results showed that scenarios describing a partner having sex with someone else or falling in love with someone else primarily evoked betrayal/anger-related jealousy, whereas scenarios describing an emotional connection between a partner and someone else primarily evoked threat-related jealousy. In addition, women experienced more jealousy than men in response to scenarios in which a partner engaged in potentially extra-dyadic online (but not offline) behaviors. Finally, compared to same-sex heterosexuals, homosexuals, both male and female, responded with less intense jealousy to scenarios describing a partner having sex with someone else. Implications for the treatment of (internet) infidelity are discussed.