Maybe he was trying, but he was involved with and EA/PA long before that. You know that.
I see no reason to think H will return. Regardless, at this point, it is time for you to be OK on your own.
I think you are holding onto for the reasons your C suggested -- enmeshment. He is your parent. You are afraid of what it means about you if you accept his leaving. I actually don't think it has a whole lot to do with him right now. When you are feeling better, you recognize the problems in your R with him and how it was not a good R for you.
At court, you did the drama, gave the judge the poignant "hope" line, rehashed the whole business with H, and you got back to this point which is somehow comforting to you.
It is at least no doubt familiar. You know how to live this way because of how you grew up. The stuff with your mother is not resolved. You are recreating it because you know it. You know that and how to have another parent. You need to focus on learning to be an adult who is not defined by what a good parent or bad parent feels about them and how that parent treats them.
You don't need a parent right now. You learned that in FL.
But, you let the familiar pull of the poor child in need of protection suck you in. Give that child-Donna the love and protection she needs YOURSELF.
Quite literally. Imagine yourself small, vulnerable, emotionally abandoned, feeling like crap. Talk to her OUT LOUD. Give her mental hugs and hug the dog. Comfort her yourself. You can do it for your own kids. You can do it for the kid you still have inside you.
Short answer: you are holding onto the pain from your childhood because it is familiar
To feel better: give that child the love and protection she deserves. You are a loving, caring adult, you have the power to give that to her.