I'm sorry you are having a tough time. I haven't been so successful in my DB efforts to save my marriage, but I have made progress in letting go and healing...so I wanted to share a few thoughts I had while reading.
I'm on my phone so pardon me for not quoting properly... but it sounds like your H was looking for validation, not just a "fixer". My H did that to me a lot, and that often made me feel inadequate. Have you read the validation cheat sheet?
And the interaction about you and your H both having plans... that resonated with me too. I would often get so resentful. But then I realized that *I* was assuming that I had to be the parent-on-duty, too. Your H is entitled to a private life. And so are you. I was advised to say to my H, in a calm way, "hmm. I have plans that night too. What do you think we should do?" If he pushes it and suggests you should cancel, stay calm and say, "I'm sorry I don't tthink I can do that. Is there a solution that would work for both of us?" What would you have done in the past if you both had gone out together?
I know how tough this is... you can see what a Hard time I've had letting go if you read my thread. But the less I try to control, and accept his choice as reality, even though it hurts, has changed our dynamic.
Your H won't come back if he thinks the M will be more of the same (controlling, lack of support). And even if you get D, do you want to be adversaries with him? Letting go of that feeling of "I didn't deserve this" has been the hardest part, and still makes me tear up when I think about it. But perhaps there is a way to see the positives... a chance to grow, a chance to find someone capable of being a true partner with me.
