Why do most societies take a more negative view of men cheating than women cheating?

Whenever a woman cheats society as a whole doesn't really see it as a big deal, she won't lose friends over it, her friends and family, men and women alike will rally round her during the divorce.

They'll tell her it's not her fault and that he's the bastard really. In contrast the man she cheated on will get no support at all. In fact he is more likely to lose friends and respect over it than her because he will now be regarded as a weak man who couldn't keep his wife under control, a pathetic specimen who people don't want to be associated with.

In contrast if a man cheats on his wife society as a whole sees him as an utter piece of shit. Men who cheat on their wives become objects of hatred.

This seems to be the same in most countries, the woman cheats on her husband - no big deal, he's obviously just a weak man. The man cheats on his wife - he's scum and a piece of shit.

Why do most societies take a far more negative view of men cheating than women cheating?

I think it's because even though most societies practice monogamy in theory, deep down most cultures recognise that women on average are a lot more desirable than men are and likely to be hit on by men constantly and generally far more prone to hypergamy and cheating.

Most societies deep down put the expectations on the man to hold the relationship together and be a strong enough husband that his wife does not stray. If the wife cheats then society sees that as failure on the man's part to be strong enough and hold the marriage together and therefore deserving of no sympathy.

In contrast most societies take the view that men should be more content with monogamy and more able to remain faithful to their wives because ultimately men are on average less desirable than women, so if a man cheats he has made an active effort to cheat on his wife and make the effort to pursue other women, therefore society regards this as worse.

Essentially, even though most societies practice monogamy in theory and treat men and women as equal partners in a relationship, in reality polygamy and being unfaithful is seen as far more acceptable for women than it is for men.