Colorado,

While I don't think anyone can guarantee that a therapist won't drop you, good therapists understand that therapy requires trust and will help you to make it a trusting and comfortable relationship. Like all doctors, there are good ones and bad ones but in my experience all of the T's I've had have been very good at allowing me the time to trust them and to begin to talk openly. Like KD said this may be a very good question to ask him, to let him know your fears and present an opportunity to begin the trust relationship.