I appreciate you taking the time to write back and provide more details about your question. This information helps me to answer your question more thoroughly.
Whether transference and countertransference is good for the therapeutic relationship depends on which theorist or school of thought one adheres to. Regarding your specific situation I believe it is unhealthy that you are still focused on your ex-therapist. You and she ended therapy over three years ago. You have tried to contact her for the purpose of either reconciliation or closure. What you may be overlooking is that she gave you closure. She explained that her supervisors advised her to terminate and then ended treatment. Your therapist probably did not end the relationship unexpectedly. As you mentioned, you and she discussed termination. This should have served as sufficient closure. She does not owe you any further explanation.
You cannot force someone to have a relationship with you. When it comes to relationships, you usually do not get to vote on whether or not it will continue. If one person in a relationship decides that they no longer want it to continue then it’s over.
The problem seems to be that you cannot accept the fact that the relationship is over. I would recommend continuing to work on this issue with your current therapist. You should stop attempting to contact your ex-therapist. You should also stop sending her gifts.
I understand that this will be a difficult process but it is not healthy for you to continue to focus on the past. There is important work that you need to do in your current therapy to help put this relationship behind you. It won’t be an easy process but it is important that you realize the truth and come to terms with it.
Thanks again for writing back and providing more details about your question. I wish you well.