It's clear you know you have to leave, you are just struggling with how to do it.

Enlist the aid of another therapist. Call around and interview them over the phone. Get referrals. Find someone who understands boundaries. Explain that this is an issue for you and you do not want this kind of ambiguity; you want a therapist, not a quasi-friend. If you find one that sounds OK, make an appointment with this person as soon as possible.

The day of this appointment, or even during the appointment, call your current "therapist" and say, "I wanted to call and tell you I am switching to a new therapist. I wish you the best, but I haven't been getting what I need out of our therapy, and need to move on for my own healing." Do not answer any calls or emails or texts that you receive in response to this. Cut this person off completely. Continue going to your new therapist and rely on that therapist's support to help get you out of this toxic relationship. Top of your agenda for therapy: why it is that you are so worried about "hurting" another person that you let them hurt you.

This sounds like a nightmare. There are good therapists out there.