Oh, Lea. I feel so awful that you're feeling bad and wish there was something I could say to help. How are you feeling now, a bit later in the day?
I thought your comments about H's total commitment to his course of action were interesting, actually, and more in line with someone who's compensating for something. I guess I think that his absolute surety that it's over is an act- he's NOT sure, so he's acting as though he is in the hope that he will then feel that way. Remember to believe none of what they say and only 50% of what they do. Your H reminds me a lot of what Al's other half said to her when he left. But look at them now? I genuinely believe he can't let go of her (and why should he- she's ACE!)
That you're going to share joint custody of your dog is good- it'll give you opportunities to DB and interact with him.
Take a deep breath. You're going through one of the most stressful things anyone can, so don't apologise for being upset at all. It just shows what a sensitive and caring person you are, and is a testimony to the commitment you made when you got M.
L.xx
PS. While I remember it, there was a success story from someone (Married_three_months) on DB a couple of years ago. As you can guess from her name, she'd been married three months (!). It might be worth having a read of her threads when you get time (they're in the success stories in the resources section- I don't think she posts any more). Reading her story helped me a lot at the beginning.