I thought it might help you to weigh in as a caregiver of a bedridden husband who has such pain issues he can barely stand to be touched, and often can't stand to have sheets covering him. I have no insight for the physicality of intimacy, but I thought if I expressed some of my frustrations it might help you with your feelings of being a burden or losing touch with the relationship that you enjoyed with your husband. It may not be quite the same as I do believe that men and women view their roles differently, so please take whatever you can use from my post.
My husband has essentially been bedridden since January of 2009, his illness also rendered him blind, and he also has some dementia issues, so there are several cerebral things we can no longer share either. I miss his former ability to be able to make me laugh, to learn new things together, and to have him explain and teach me simple things I never learned (like righty-tighty, lefty-losey). What is hardest on me is that I sometimes feel that I have allowed him to become merely a patient, rather than a husband, friend and partner. So, I would advise you to take inventory of what you still have to offer for your family (it looks to me like your personality is still intact, and you still have the essense of you, right?!?) focus on those, and re-build from there. I sometimes feel like the only time my husband talks to me is to either tell me that he is in pain or needs something (water, food, radio, cleaning up, he pretty much needs total care). Unfortunately his pain is the type that we seem to have exhausted all of the alternatives for, so I'm often unable to help him which tears my heart right out.
So, please try to take your focus away from what you can't do, and embrace, celebrate and build on what you can do. Take inventory on your interactions with your husband and if you can, make sure that all of your interactions aren't caretaking requests. Kudos to you, by the way encourgaging his bike days, I'm sorry that you are in so much pain you can't ride in a side car or something along those lines.
I hope you are talking together about the career decisions, as much as he feels the call to the music ministry, it may be more of a stress on him to not bringing in more money, and there are probably some creative solutions out there. Perhaps you can create some kind of homebound ministry, perhaps having elderly or latch-key kids call and check in with you to let you know they are okay, and to have a plan for when they don't call.....
Hope this is helpful, I hope I didn't offend you in anyway. And you are one of the lucky ones to have a husband you can trust to stand by you!
Best of luck, this isn't an easy road for any of us, for sure!
Sandy