Telling your SO

When I was about 7, my cousin, who was 12 at the time, started molesting me. I didn't really know what was happening--just that when he babysat me, he touched me. Then, when I turned 8, he started making me give him blowjobs. I didn't know what was really happening. I thought it was normal. When I turned 9, he started raping me. I still didn't think that he was doing anything wrong. I knew that it hurt, and I always wondered why he did it, but I still never told anyone. By the time I turned 11, I knew what was happening, but I still didn't tell anyone. I thought that they wouldn't believe me since it'd been going on for so long. They'd ask questions like, "Why didn't you tell us sooner," and "Are you lying?" So, I kept my mouth shut. He stopped when I was 12, and he realized that I had started my period. He thought that he might've got me pregnant, so he took me to a clinic. He told them that we were dating and that I needed to see if I was pregnant. After finding out that I was, he told them to abort the baby. I was sacred out of my mind and he was my cousin--practically a brother to me--so I agreed. After that, the abuse stopped. He went on with his life as if he hadn't ruined mine. 

So, I just need some help. How do I tell him that I was raped? I've never told anyone, so I don't really know what to say to him. I don't want him to get mad at me or leave me or anything. He says he'd never do anything like that, no matter what I tell him, but I just can't help but feel that being raped is too much for him to handle.