Other than this scheduling issue, do you like this therapist? If you do, don't shoot yourself in the foot by totally quitting working with her. Every other week is not ideal for you, but being completely without a therapist is probably worse. If you don't like this therapist, then I would guess that leaving her has more to do with that, which would be completely justified, than it has to do with the scheduling. If every two weeks is the only option, find a way to make use of what you can get. Isn't some professional support better than being completely without support at all?