I think we can all agree that in most situations jealousy is not a nice feeling to experience. With background sentiments of anxiety, possession, insecurity, anger, resentment, envy, and mistrust, jealousy often grips us out of nowhere, and it holds on strong. But there may actually be an evolutionary reason behind these feelings, which may explain why straight males tend to experience jealousy stronger than other individuals. (Though be forewarned, this theory may trigger patriarchal anxieties.)
Evolutionary psychologists theorize that back when all humans were living on the African continent, males were responsible for protecting the social group and providing food, while females were responsible for maintaining relations within the group and raising children. Scientists hypothesis that male jealousy evolved in order to assure that females weren't taking resources from the group and giving them to members outside of the group. Female jealousy evolved from more of an emotional basis, with the concern that a male would betray her and thus fail to adequately protect the resources for her offspring's genes.
A modern-day study involving 64,000 Americans of all different sexual orientations was able to confirm the hypothesis that male jealousy is stronger. The study found that heterosexual men experience jealousy over sexual infidelity the most intensely; ultimately straight men are concerned if their partner has had sexual affairs with another person. Heterosexual women, gay men, and bisexual men and women were all more concerned with emotional infidelity, worrying that their partner might fall in love with someone else. Have you experienced jealousy in this paradigm, or are you experiences dissimilar?