I was reading a bit about this condition, both Endometriosis and dyspareunia. The estimates of affected women in the general population varies (naturally), but millions have one or both conditions. Uteral lesions seems to be the major cause and, obviously, can be corrected by surgery, however, the psychological "wounds" are even more significant because of association. So called "phantom pains" like those felt by amputees can last long after the surgery is performed.

I agree with what others have said here about experimenting with non-penetrating sex and particularly the "go slow" approach to try to assuage the fear/pain factors. Similar types of fear/pain/insecurity can occur with women with other conditions, of course. I was with a woman over a few months who "found it impossible" to produce natural lubrication. It was a psychological problem affecting her "normal" physical responses to stimulation. And it took slow, careful, sensual "shifting" of her perception of stimulation as well as making her aware of the "good" sensations of (synthetic) lubrication to help overcome whatever the psychological 'block" was.