Please help

When I was in eigth grade I was sexually assaulted multiple times (does that make it abuse?) by a class mate. We've gone to the same school since fifth grade and are about to be juniors in high school. I know that it's a bad feeling but something about me wants him and he's a heartless douchebag (pardon my language) so I know he won't care how I feel. I also have a boyfriend I've been dating for a little over a year who I am insanely in love with but this guy I go to school with a always seems to draw me in and I can't ignore the temptation to just give in. My boyfriend knows that I've had these feelings before and he's helped me get over them but they've come back and I feel like my boyfriend has changed a little bit. I'm afraid to tell him what I am feeling again because I'm afraid he'll think I'm going to leave him. Any advice?