I've been there. When I lived with a boyfriend, I couldn't stand being in bed with him. I didn't yet understand about my trauma and PTSD so I thought it was a crazy thing about me and I pretended I didn't feel that way. Ooh, those were hard times.

Sannah is right, though, if you want to be okay with it, you'll have to face your fear. It would help if you have a T who can walk you through the steps of exposing yourself to the feared situation and also give you ways to cope with your anxiety during the process.