I was rereading this thread and came across your post to it (sorry I missed it before):
as a 21 year old does it seem strange that i dont think about sex at all?
In light of what I know about your horrific abuse experiences, no, it doesn't seem strange to me at all. You already have the explanation in the rest of your post: for you as a boy, sex was about abuse, and now, even though it's all over, these images are still with you. So sure, for you, even as a healthy 21 yo, sex is something that you don't even want to think of yet. What you are doing here is protecting yourself emotionally - nothing more, nothing less.
The big question is how do you feel about this? It would help you as lot to let those feelings out. And THIS comes right back to something I just said to you on another thread: please don't fall into the trap of letting yourself be defined by the faults or crimes of others.