Definitely I would say the best thing to do in this case is just to tell him, very clearly, about what happened and how it affects you. He'll be glad you trust him enough for that. Try not to get too emotional while telling him -- you don't want to frighten him. The best way to do this is probably to try to be very direct and to the point, and, perhaps most importantly, to avoid a discussion about it at all costs. (If, later, you want to have a longer, more detailed conversation about it with him, that's fine, but it shouldn't happen the first time he hears about it. He'll need time to digest the information.) Just state the facts and leave it at that.
What's more, I would try not to directly mention that you're bringing this up because you've noticed he seems ready for sex and you're not. This is a very tricky subject for people to deal with, and you don't want to bring it up in a way that will make him feel guilty. You might try introducing it with, "there's something I think you should know that's a little difficult for me to talk about", or "If you've noticed me seeming a bit 'edgy' lately, here's why ...". He'll get the hint, but without feeling as if he's done wrong. Yes, this would be irrational of him to think, but believe me, he's likely to if you don't tread around the subject with some caution.
Gradually you can have more and more open discussions about it (if you want) and what it means for your sex life, but give him some time to wrap his head around it first.
(Also, this probably seems a little meaningless, but I am so sorry that you had to endure eleven straight years of rape, and that even though it's over now it's still haunting your relationship. The good news, though, is that any guy with half a heart will understand that he needs to accommodate your pace in the relationship. Good luck, I hope all goes well.)
