Mens' sense of security with a woman does not come from the relationship

Women have a massive fear of being left pregnant and abandoned. To alleviate that fear, women seek a sense of security that comes from a man who likes her for who she is so much that he's happy to stick around even after she ages into banana tits. Then she wants him to sign a literal contract that promises the rest of his life to her. If he does all that, then she can breathe a sigh of relief that he'll at least stick around to help raise the kids. Okay, fair enough. Understandable. But why would you expect this to apply to men? We don't worry about being left pregnant and abandoned. Finding someone who likes us for us isn't particularly a huge goal because that only helps with relationship longevity, and a longer relationship doesn't really address any of our concerns. Same with commitment - it doesn't really help with anything we're worried about. We just get less out of relationships than women do.

So then what is the primary male fear - the male equivalent of what being left pregnant and abandoned is for women? It's raising another dude's kid. It's not practical for a man to be with a woman 24/7 to see what she's up to. And no man wants to bet on being the winning contestant in the sperm lottery when the cost to play is 20 of the best years of his life. So a man's entire sense of security with a woman comes from his assessment of the likelihood that, should a kid pop out of her then it will be his kid. There are basically only two things that factor into this: how much she wants his dick in particular vs how much she wants those of other guys.

Note that these two things are not mutually exclusive. A man can both really like being around a woman and want to be with her for a long time while simultaneously that woman can really prefer that man's dick in particular over and beyond all others. There's nothing in principle that creates a zero sum game where men getting what they need means women can't get what they need, or vice versa. But instead we engage in gender wars because women incorrectly assume that men's obsession with sex and relatively blasé attitude toward relationships must represent a threat to women.