I want to go to prom but..

So there's this guy I really like, and I want to ask him out to prom. But the problem is, is that there is his psycho ex girlfriend that keeps bothering him ajd following his every move, and two other girls that claim they've had a history with him, even though I've known him for two years and they've known him for one. I really wanted to date him too but I know right now isn't an option because he's already stressed with the other girls so I never ask. But I really want to be able to go to prom with him and I waited to ask and now that I have the chance, I dont know if this is maybe a sign to just go for it.. I fear rejection from everyone amd especially him so I really am

nervous. please help ;_;