I think mine started with a traumatic stress syndrome reaction, but I was always a
very sensitive person and had a hot temper. My diagnosis originally was Cyclothymia; who knows what it is now. (I think it's still Bipolar II.) But I'm content and live comfortably.

You will be better; your post on the relationship with your X is reason enough to develop bipolar from traumatic events, in my view. Stay with therapy, please, until you get the stress of that relationship resolved. Your bipolar disorder is likely to get better the more you care for yourself.

You seem very intelligent and willing to get to the bottom of the obsessive thinking.
You can do that, believe me.