These all sound like perfectly understandable emotional responses. And I think I'd feel a mix of the same. I think knowing that you can tolerate those feelings is a good thing too.

My T talked with me the other day about "functional obsession" and how I threw myself into my relationship with my ex-T in part to avoid needing to deal with the very real problems in my marriage. I think she's absolutely right. I think I was also looking to get my intimacy needs met by my T, since I had pretty much given up on my H being able to meet those needs in a satisfying and not triggering way for me.

My current T called herself a transitional object, which was a way I hadn't previously (or at least explicitly) thought about the T relationship. That I could "use" her in the ways I needed to, with the ultimate goal of taking on those functions for myself. I think this is similar to how your T has framed therapy.

All of this to say that I wonder if some of the compulsions you find yourself doing, or obsessions you find yourself having, stemmed initially from avoidance of intimacy with your H (or just issues with intimacy with your H). I'm talking way back to your early T's. And then perhaps over time, the obsessions/compulsions took on a life of their own. It seems like you've been doing some exposure therapy on our own, for example, by responding to obsessive thoughts about your T with resolve not to compulsively "check" on her (e.g. via FB). Could you imagine extending this, so that gradually you can learn that the anxiety that comes up around your T, and ultimately, about intimacy, will reduce on its own without the need to resort to compulsions?

I think that attachment certainly plays a role too, but idk, there has been something freeing for me about looking at all of this T relationship stuff in a new light. Hopefully there's something helpful in there for you