What could cause an adult female to be unable to have an for years despite extreme arousal?

My friend's fiance wants her to see a therapist, possibly even a hypnotist, for her ual problem before they get married. She's asked for my advice because she knows I see a therapist myself, but my issues are not ual in nature, and I'm unfamiliar with such a problem. My friend is in her fifties, and this will be her second marriage. She says she has rarely been able to have an , not just with her current fiance, but with anyone or in any cirstance. I asked, and she said not even masturbation does the trick. She says she has a high drive to HAVE , gets extremely , and does enjoy , but always gets just to the brink of an , and no further. She says her fiance is frustrated by her problem and by the fact that she says she really has no idea what could be inhibiting her in this way. She said she THINKS it's rooted in childhood because it's always been a problem, but not exactly sure how, which I find strange. Could a hypnotist help with something like this?