I can't remember anything, but should I tell my boyfriend?

I was raped three years ago by a former coworker. I have pretty much moved past it. I met my boyfriend a year after my rape and he knows everything and was very supportive. About a month ago I went to a friend's graduation party. We took a party bus from bar to bar and I got very drunk. At the last stop I was blacking out. I don't remember getting there or anything I did really I just have fuzzy memories of the being there. I was so out of it that the bus left me and I was stranded at the bar completely intoxicated. Apparently a "friend" I went to high school with offered to give me a ride. I think we kissed in the car but again I really cannot make a clear picture in my head. He took me to his house. I did not ask to go there and I remember not wanting to be there but I don't know if I said anything. I have pieces of fuzzy memories of being at his house. I know other people were there but I can't remember who. The next memory I have is being in his living room on the couch in the dark. I go in and out of blacking out. I remember him pulling at my clothes and I don't think I said no, I don't think I said anything. I remember at one point thinking I was really with my boyfriend and then realizing he was a different person. After that I have no memories. The next think I know I am on his floor of his living room at like 4:00am and my shirt was on half way and I only had my underwear on and my crotch was really sore, like somebody kicked me. I frantically gathered my things and started heading out the door. My car was still parked at the bar we started at so it was about a 5 block walk. The guy stopped me and said he would give me a ride. I said I was fine but he started getting his keys. I sat in his car silent. He acted as though everything was normal. He dropped me off at my car. Later when I got to my house I text him asking what happened and he acted like it was nothing. I begged him please not to tell anyone about whatever happened and he agreed. After that I called my best friend and bawled into the phone and told her everything. I told her how I can not remember anything but tiny bits and I don't even know if those are accurate. I have not said anything to my boyfriend about it. I am afraid he will think I cheated on him. I know that if you are drunk it isn't your fault and it is rape by law but I am afraid he won't see it that way because he will be hurt. I would never knowingly cheat on him. I don't want to keep things from him but I am afraid telling him will cause him so much pain and ruin our relationship. I don't know what to do. I feel so ashamed. A part of me thinks it's my fault because how could something like this happen to someone twice if they weren't putting themselves in the situation even though I know I shouldn't think that. I love my boyfriend with all my heart and I don't want to lose him over this but I don't want to lie either. What should I do?