I can't let myself climax

I wonder if you can advise me please. I am a single woman with a healthy sex life who has never experienced an orgasm, either with a partner or on my own.

I sought the advice of my helpful GP who in turn put me in touch with a psychosexual therapist. After a few meetings the only help I was given was a list of books to read and exercises on relaxation, which I have done.

Apart from not experiencing an orgasm I have no past bad experiences or childhood traumas. My partners over the years have all been very loving and non-judgmental and have never put pressure on me or made me feel inadequate.

I want to experience at least one orgasmic experience - just for me. I came close to experiencing one many years ago. It took me by surprise and I think I panicked when I felt unfamiliar feelings in my body.

Since then I suppose I have a mental cut off when I make love. I really would like to move on from the frustrating 'plateau' phase so any advice from you would be extremely welcome.