It was never a case of me doing something and thinking I deserved sex, she just never wanted to. I expressed my needs many times over the years, but it never changed.
Most guys do not know how to turn a woman on. You have an opportunity right now to start doing some focused research/learning in this area.
When I was in the thick of my sitch, I was visiting the book store weekly, browsing the self-help areas, and reading 2-3 books a week.