I think it is fine to acknowledge the role a T has in our healing. (I owe my T a lot for that!) I don't see the two things you mentioned as being necessarily connected. Like say that together with another artist you painted a magnificent painting that hangs on your wall. If the other artist should move away, the painting does not disappear. It has been created and it endures. The changes you are making in your life (the healing) will not go away if someday your T leaves the scene (even though her absence is painful to contemplate right now).