The concept is studied in human and non-human primates in the field of evolutionary psychology.
Evolutionary psychologists have suggested that there is a gender difference in sexual jealousy driven by men and women's different reproductive biology.
That is, the higher the level of social comparison, a personality characteristic referring to the tendency to compare one's characteristics with those of others, the more jealousy various rival characteristics evoked.
See main page: Mate guarding in humans One behaviour arising from male's sexual jealousy towards their partner's sexual infidelity is mate guarding.
Therefore, jealousy is likely to be evoked in females if they feel that their partner may leave them for another woman; this has been shown to be more likely to occur if the male commits emotional infidelity.
Many studies have shown that females tend to place a stronger emphasis on the emotional aspect of infidelity, over the sexual aspect; it is this emotional infidelity that becomes the focus of female sexual jealousy.
Sexual jealousy is a special form of jealousy in sexual relationships, present in animals that reproduce through internal fertilization, and is based on suspected or imminent sexual infidelity.
It is founded on the instinct of keeping genes in the gene pool and expecting sexual partners to care for the offspring.
Furthermore, statistics on domestic violence continue to show that in relationships it is primarily men who are the abusers, rather than the women.
On the other hand, it has been suggested that because it is the woman that ultimately chooses the mate, aggression caused by infidelity is directed at the rival female.
In contrast, women invest a lot of emotion into a relationship and will experience a threat to their self-perception when a partner commits infidelity, hence why women are more concerned with emotional infidelity rather than the sexual kind.