This guy kills me uhggg?

Be straight with him and tell him he is acting like a psycho or if you don't want to be too harsh. Tell him that he is acting clingy, too obsessive or creepy. You can always have one of your good guy friends tell him that he is your boyfriend. Maybe have a brother or sister tell him that they don't appreciate the way he is acting toward you. That they would like it if he does not hang out around you again. If you know a girl that likes him maybe you can play match maker. Good luck.