When individuals ale asked which event would upset them more-a partner's em
otional infidelity or a partner's sexual infidelity-among heterosexuals mor
e men than women select a partner's sexual infidelity as the most distressi
ng event, whereas more women than men select a partner's emotional infideli
ty as the most upsetting event. Because homosexuals' mating psychology is u
nlike that of heterosexuals, the present study examined which of these two
events is more upsetting in a sample of 237 Dutch homosexuals. In support o
f our hypothesis it was found that, whereas gay men more often than lesbian
women chose a mate's emotional infidelity as the most upsetting event, les
bians more often than gay men chose a mate's sexual infidelity as the most
upsetting event. In addition, analyses showed that the effect of participan
t sex on infidelity choice was mediated by beliefs with regard to the co-oc
currence of sexual and emotional infidelity. Apparently, with respect to ch
oosing the most upsetting type of infidelity of their partner, homosexuals
resemble heterosexuals of the opposite sex. Several explanations are discus
sed for this finding.