I totally understand where your coming from I was in the same kind of situation with my wife but admittedly probably not as bad as your situation. I struggled with my wife just doing it for me and not "really" wanting it. I think that many times that just by taking the crappy sex that was offered I made things worse. I remember a few times where she would put a pillow over her head during sex like I wasn't even there. Took me a while to not accept that anymore and I wish I had never accepted the "scraps" that were thrown my way. It was too late though our relationship had deteriorated to the point where she was uncomfortable with any touching from me.