Men have to expend effort to cheat. They have to download dating apps or step outside their normal routine to socialize and meet women. They have to *work* for the sex.
I think that's part of what makes it so heinous when they do. There's this sense of "you wanted someone else badly enough that you were willing to go through all that effort and now you're copping pleas?"
With women it's a matter of just saying "yeah sure" and giving in to the daily approaches that men make. Female beauty and attention is so prized that they literally can't just step put the house in a t shirt and jeans without being hollered at or post a Pic on social media without thirst flooding the inbox.
It's far easier for them to cheat and it's what fuels male jealousy and refusal to be okay with them going to the club on their own or going on a vacation without their man. There's the assumption that after a couple drinks and a "you got some pretty eyes, my name Corey

" ngga approaches they'll throw that ring away like Bobby shmurda hat and give him that throat. Paradoxically women seem aware of this fact and yet still act confused when a man is jealous and wants her to only go out when he's around.
People cheat because of lust, and some times out of spite. An immature individual might cheat back after she's been cheated on instead of just throwing the relationship in the bushes and moving on.
I'd also add on insecurity as a reason why men cheat. They need to know they still have value in the dating world especially if they weren't getting much women before and had a glow up. Some men will act cool with his girl going out on her own and having girls trips because he's busy cracking his side piece's back while his girl is away. That woman is in an open relationship, she just doesn't know it. He assumes she's gonna cheat on him anyway so he might as well get some cat himself while she's gone. It's a win win for him because he seems like he's secure and not jealous but in reality he just doesn't care. If she splits up with him, he's got his back-up girl.