How to get over ptsd in the bedroom?

I've been sexually abused in my past and now I fear that I can't "let myself go" in the bedroom.

The guy I'm in a relationship with, I trust with my life, but I still can't manage to just relax and enjoy intercourse. It's like I have a mind block that is stopping s3x from feeling amazing. I used to be able to squirt and now it's a very very very rare occasion. Sex used to hurt for me at times.. And now it's like I don't feel very much. I just want to get the full enjoyment out of intimacy.

Help!!!!