I suppose that could depend on how you go in viewing the sex. I'm just talking out of my ass, but that could be a way that guy weeds out girls that think having sex implies ownership.
Or he's just another guy that loved his ex but his dick is somewhere else and he hasn't figured it out. People are people, she feels shitty, he loves his ex, you want a decent relationship, it's all fine. Being weird isn't easy at any point in life.