Aggression in men has an adaptive value. Men are more likely to experience sexual jealousy because of their fear of cuckoldry. Because men are more prone to parental uncertainty, they risk unwittingly investing resources in children who aren't their own. Sexual jealousy and the aggression which it can cause, therefore, evolved to deter females from sexual infidelity and hence minimise the risk of cuckoldry.
To do this, men have evolved retention strategies to deter mates from infidelity. This includes direct guarding, in which a male is especially vigilant to their mate in order to restrict her sexual autonomy. Retention strategies can also include violence against the woman. In extreme cases, an unintended consequence of this evolutionary behaviour may be her death (uxoricide).
Research has supported the relationship between male retention strategies and violence. Shackleford et al. found that men's use of retention strategies was positively correlated with violence scores. Women's responses also confirmed this, with evolutionary male retention strategies leading to violent behaviour towards them.
The explanation of uxoricide as being a consequence of sexual jealousy cannot account for the fact that younger women are at much greater risk of uxoricide regardless of their partner's age. The finding that men kill their wives when they're most reproductively valuable contradicts evolutionary logic. However, the evolved homicide module theory explains this by pointing out that a partner's infidelity carries a double loss for a male. He loses a partner (which damages his reproductive fitness) and another male gains his partner, increasing his own fitness.
A problem for these evolutionary explanations of aggression is that most studies of infidelity have focus solely on men's retention strategies and violence against women. It has been argued that women practise retention strategies and carry out assaults on their partner as often as men do. This would...