Unfortunately due in part to how many healthcare practicioners are trainned, bdsm is taught to be a high risk behavior that doesnt fit within the normal paramaters of society so its very very hard to find a good therapist that is able to see past the bull.

This trend is however slowly changing.

Short of switching therapists, you may wish to educate her on the reality of the subject (bdsm relationships) before allowing her to proceed with a bunch or pre-concieved half truths about this way of life.

Mabey even send her to this web site to do a little reaserch.