I was once where you are and I am happy to have left that horrible experience far behind. I was stuck in this pointless suffering with each therapist I had. You are certainly not the only one and you are far from being an exemption from a common rule. After having heard so many harmful therapy stories, I am convinced that your experience of transference is quite typical, unfortunately. I believe that those cases when it gets better are rather exemption from a general rule that it causes pointless suffering that gets worse over time and leaves the person more traumatized than they were before therapy. This issue, unfortunately, doesn't get honestly addressed by the profession.

The good thing is that you are aware of the fact that this is not a therapeutic experience and that you want to end it, even though you feel too weak and too dependent to quit right now. Just continue to be aware of this and don't buy into the idea that this is something you need to "work through" with your therapist. You won't be able to work it through by endlessly talking about it and writing letters to your therapist about it. If anything, it may only get more intense and more painful. I am not saying not to talk and not to write about it. Do whatever you need to do in the moment. Just keep in mind that none of those things will liberate you from this obsession despite what your therapist might say. In order to get liberated from this you'll have to do your own work "on the side". You'll have to figure out on your own what kind of old sore spots and old longings your therapist triggers in you that give rise to your feelings. At the same time, while doing your own work, it might help to space out sessions and/or to take brakes in order to reduce the frequency of seeing this person. You can also consult with someone else in the process. You have the right to get a second opinion so it may not be a bad idea to try someone else while still seeing this therapist. Also, you may consider trying some alternative healing methods that address emotional problems differently. Some types of body work do that among others. Eventually, you'll be strong enough to leave this situation if you set your intention and commit yourself to it. This is how I did it.