While I do not suffer from this disorder it is my understanding that most of these cases are due to psychological issues or psychological mixed with medical issue, but never medical issues alone.

With that being said may I ask you about your past sexual experience?
Any sexual abuse in your childhood or upbringing where you were told (and now believed) that sex is bad?

If the main reason behind your pain and discomfort is emotional then I suggest some counseling to help you heal from the past. If the main reason behind you not having sex if the physical pain then might I suggest using some pain pills and a good vaginal lubrication with minimal penetration of the penis.

I have gone through spells where it was to painful for me to have sex due to my Fibro and RA and I usually helped my husband out manually when I could not be with him physically... have you tried this?