How do you approach this?

Sex hurts it's uncomfortable and painful. My Sex drive is nothing. I have Sex with my husband only for his pleasure I try to fake it but that's even hard to do now. It wasn't always this way and it's only been the last few months. I don't really want to bring it up to him because I don't want him to take it to heart but I need to go to a doctor and he's going to want to know why. I don't and won't lie to him I just don't want to hurt his feelings because it's not him it's me. Any advise on how to bring up this subject?