Pardon me for jumping in where I probably don’t belong as it's been many years since I was in therapy.

How about opening up a discussion such as

“I’ve given this a lot of thought, and I don’t mind helping you, but for my own comfort, I should probably get a different therapist. Would you be OK with that? (or What do you think of that?)”

This would be in your own words of course. This puts the ball in her court. At the very least it will open up discussion on the topic and let her know you feel some discomfort about the situation.