From what I'd read, it was because Rihanna wanted to break up. It'd be more justifiable if he actually had gotten herpes, but I doubt he did. He's got a shitty temperment, and to actually FIGHT a girl, proves it; He's a complete pansy ass, a complete faggot. I've heard weirdo black dudes singing in public who sounded like him. Black guys who sounded like black girls, with lisps. Think the temptations meets eddie murphie with a major gay lisp; THAT sounds like Chris.
The only reason I actually bothered looking into this was because I thought she had herpes, and although I'd feel bad, I really wouldn't feel that bad, it's just funny to know. She's no one special, she makes generic pop songs that fade away after a few weeks.
It's like hearing that Miley Cyrus caught the HIVs from her father after taking nude pics to put on the net, it's sad, but nothing you wouldn't expect.