(((((Maria))))) Wow.... I don't check piecing for a few days, and look what happens!
It feels to me like you have spent the past few months (maybe years) climbing the ladder to the high dive, you've walked out to the end of the board, and now..... you look down, and it's scary! Of course it is! But you climbed up there because you wanted to jump. You knew that you could do it. I know you can do it. Have the faith in yourself, in your H (who is saying incredible things, compared to even a few months ago). You can jump, and it will be ok!
Don't think of this as trying to rebuild your old M. You are building a new one! He's a new man, I think he sounds like a better version of the man who left. Maybe he needed to learn some things, to grow up? And it sounds like he did. Was it "fair"? Of course not! But maybe it's the way it had to happen.
See a IC, I think someone that's trained in this could really help you get through. Just make sure you make it clear what you want... some C's I think will take the easy way out. Leaving him would be the easy way, right now, but I don't think it is what your heart really wants.
I can't believe I am writing this... I never thought he could do it, and it really seems he is. You have the actions, you have the words... he is finally doing the work, Maria!