I've not been in this situation before and it does bother me a bit. He and ex wife appeared to have got into a toxic relationship and she cheated with his friends, he went to prostitutes whilst working abroad.
He's quite open about this, they obviously weren't good for each other. 2 children involved but they seem relatively unscathed and he and ex get on fine now.
I'm not sure how I should feel about this though, we're not super serious (and he wouldn't be able to afford it at the moment anyway!) but it does make me feel a bit uneasy. He's been quite upfront really and said it was control as his marriage was crumbling.