I'm really sorry you are struggling right now. As a fixer you are really struggling because you can fix your marriage without your H participation. You brain thinks that getting your H to make a decision no matter what the decision is going to make the pain go away but it won't. Your H using the threat of mediation if you don't let him see the kids more is very manipulative on his part. What you really need to do is give more more space then he is asking for and go out and live your most exciting life. If he wants to be a part of then great but if he doesn't that's ok too because your life is awesome anyways. I always amazed when posters are upset that aren't getting breadcrumbs and temp checks. You don't want that because that just messes with your mind.
If you truly know your value that don't settle for anything less. Time and space are your friend right now.