Jealousy occurs when you feel a valued relationship is threatened. In an evolutionary perspective, jealousy function as a way to motivate people to fight of threats against their relationships. Men feel a stronger sexual jealousy than women do. The reason in an evolutionary perspective is that female infidelity and hence the risk that other men impregnates their partner reduces the man’s possibility to reproduce himself. For women the strength of the feeling of sexual jealousy is dependent of the risk she feels there is that it will make her lose her partner to another woman. The sex itself don’t have the same importance as for men.
Strong feeling
Sexual jealousy is a very strong feeling. It can lead to loss of self-esteem, feelings of sadness, depression, rage, embarrassment and humiliation. It is also the primary source for domestic violence and the leading course of the murder of mates or ex-mates. As men react most vividly to sexual jealousy, it is not surprising that they have the most violent reactions.
Infidelity
In many studies, it is documented that men react more to sexual infidelity that women do and than women reacts more to emotional infidelity than men do. These studies also finds that men spend much more cognitive time on sexual infidelity and remember sexual infidelity much more that women do and vice versa for emotional infidelity.
The strength of male jealousy is increased if their rival are conceived as more attractive. That is wealthier, have better job prospects or more physical strength. Women reacts more if a rival surpass them on facial or bodily attractiveness.
Swinging
When a man engages in swinging or the like, he is motivated by his desire for sexual variety and at the same time he is more in control of the situation. This is the reasons that many men don’t feel the same sexual jealousy in these situations. Women on the other hand don’t fear that they will lose their partner to another woman in the swinging context and hence they also feel less sexual jealousy.
Swingers often explain that they are nervous about jealousy before they engage in the lifestyle but that they after experiencing their partner with someone else a few times actually feel liberated from their jealousy and that it make them love their partner even more. Several studies find that for most swinging people sexual jealousy diminishes over time and mutual trust between the partners are strengthened. Swingers communicate a lot about sex and their feelings in general, which make them better able to handle jealousy. Sex with others becomes a natural and fun thing and is not seen as a threat to their relationships. The lack of jealousy among swinging couples make their relationships more open and trusting in general. Some swingers even express that they feel compersion. This is the opposite of jealousy where you feel joy when your partner have sexual or emotional experiences with others.
However, jealousy does occur. Some get jealous if their partner share intimate feelings with others, some if their partners have more sexual encounters with others than themselves, some if their partners kisses someone else, some get jealous if their partner receives gifts. It is dealt with by being open and talking directly about it. Most swingers make rules for their activities, which is a tool to avoid jealousy. In this way, most swingers are able to handle the feeling of jealousy when they do occur.
Source:David M. Buss: sexual jealousy, Kourtney Ty Vaillancourt: Reconstructing the Meaning of Fidelity: A Qualitative Inquiry into Swinging Relationships