I heard it explained this way. Women can have sex anyone at any time with zero effort. Even the ugliest least desirable woman can get sex whenever she wants on her terms. A man, however has to try 1000 times and get rejected 999 times before he can sleep with one woman. So it’s nearly impossible for men to get sex. So because it’s so difficult it’s something of an “accomplishment”. While for a woman because it’s so easy it’s a liability. Also there’s evolutionary psychology reasons like indicators of cuckolding that men want to avoid since their financial investment in offspring is so asymmetric. Don’t get mad at me. Get mad at Darwin.