Male promiscuity consequences

I've always felt like the consequences of male promiscuity were basically non-existent as long as they didn't knock anybody up... There's this dude in my group who fell into the whole tech bro libertarian polyamorous thing. He was very vocal about it on social media and would often talk about hanging out with high end sex workers. This was a few years back and he was really young. He had a few bad experiences and ultimately backed away from all of that.

Now he's head over heels in love with this girl who's a really good friend of mine and she wants absolutely nothing to do with him because of his past. She assumes that if he hung out with sex workers he paid them and if he was polyamorous for a few years he'll probably just cheat on her in the end. It's not even a matter of conservatism. She just finds it all very embarrassing and doesn't want to date him because of it. He seems to genuinely regret his past and says he feels like he was duped into it by people who were a lot older and made it seem normal.

Never saw it come back on a guy like that and I feel bad for him.