I have no idea of the sort of things you are thinking. However, the key here is building it up little by little. He needs to feel comfortable with everything you are doing. Your first problem is the fact that he won't discuss it with you. My belief is that the key to a great sex life is communication - in and out of bed (I assume this is what you are talking about - otherwise I am going to look like a loon). He sounds as if he is shy and doesn't want to discuss those really personal thoughts.
I can't say exactly what I would do because I don't know him, but my gut instinct is that I would say "I really need to talk to you about our sex life, will you discuss it with me". My fall back position if I felt I couldn't do that is to try seduction. Candles, music, scented oils, long massage, taking matters slowly and gently into your own hands......