I went through the exact same thing for 8 years with my ex. I just want you to know you aren't alone. I'm not sure I have any profound advice for you, but I do know one thing. This problem is bigger than the both of you. Run, don't walk, to someone that you two can talk to. A marriage counselor. A sex therapist. Somebody. This isn't one of those things you can suffer in silence. You said that there is more to marriage than sex. True. But only when it's not an issue. Believe me, when you are rejected, frustrated, and filled with self doubt because of it, it takes center stage. Likewise when your partner feels pressured, undesirable, or unamorous. You both have a lot to work out and I wish you all the luck in the world!!!