Welcome Bohemian Gypsy: I'm glad you decided to join our community. I'm sorry you have a uBPD mom. Your reference to your mom being "the ring leader" sounds comical, but I think many will understand that there isn't anything comical about it.
Good to hear that you have a wonderful therapist and a great man in your life.

I have also realized that my mother is an enmeshed codependent, uBPD. I am trying to unenmesh myself but have reached a point of crisis. She will not give me the space. I feel fearful, guilty and obligated. I am unhappy and want to severe ties with her. My entire family is dysfunctional
Have you tried establishing some
BOUNDARIES? Boundaries are for your benefit. Others won't likely agree with them, so it is up to you to consistently enforce them. Are there some boundaries you are having trouble with? Would you like to share some examples?
Reading this article on
FOG might be helpful for you. It is a common challenge that others with disordered family have to learn to manage. You are never going to please them. It won't ever be enough.
You can't change your family. The only thing you have power over is yourself, the way you interact and the way you react. By using some strategic communication skills, you can make things better for you.
You can't wait for your mom to give you the space you need, you need to just take the space.
What are some issues with other family members? Do others have BPD traits or other mental illnesses?