Getting over abuse in a relationship?

I was in a relationship a year and a half ago over the summer. I'd known him for a long time and we were pretty good friends. He was supposedly a Christian, like me, and we said that we wanted to save ourselves for marriage. This was my first relationship, so I wasn't very wise to the ways of teenage boys yet. He told me "I'll love you forever," and I was stupid enough to believe that. Over the two month relationship, he kept trying to get me to do more with him, even though I didn't want to. One night he started doing things I didn't like, and I told him to slow down multiple times, but a few minutes later he would start again. Everything happened so fast that I couldn't/didn't(?) tell him to stop, and that night I left feeling used and hurt. He broke up with me the next day. I just started at the same school as him, and he's always talking about how he's a die-hard Christian, but he's always flirting with all the girls, and I found out he had 4 more relationships the six months following ours. He told his friends about what happened and they probably think I'm sleazy or something, but I really didn't want what happened. Did he cross the line, or is it my fault because I didn't tell him to stop? I'm a teenager, and none of my family knows about this. I've asked for God's forgiveness so many times I can't count them all. I'm struggling because I feel so abused by someone that I thought I would be able to trust, but then I just tell myself it was my fault for what happened. How do I free myself from the guilt I feel from something I never wanted?