Hi there PM. You sound like you're doing everything right at the moment. Keep it up.
As for what you say about trying to encourage your H to take more of an active roll in his children, I think that would be a good thing. The way I see it is that he must be very unsure how to be around them since he's never really had that active a roll with them. Although I saw my S every day, I was always the less active parent due to my work. I would always look to my W for validation any time I suggested something for him. That was suddenly taken away and I was left to make the decisions myself when I had Wee Man to myself. It was a steep learning curve for me even though I'd already had a lot of interaction with him every day. There are times I still feel like calling my W for advice when something's going on with him. I do manage to stop myself though as I don't think it's healthy. I need to prove to my W that I'm a good Dad and can handle whatever my S gets up to. It's driven by fear of doing something wrong. I can see that this is probably where your H is as well. His bitterness with you when you leave him alone with the kids may be born out of fear. I know because I've experienced it to a lesser extent.
What you're doing with congratualting him with any good parenting skills he exhibits is a good thing. It will help to increase his confidence in what he's doing and therefore increase the pleasure and pride he has while spending time with them. He struggles to spend time alone with them because he's never had to do it before. Parenting is something you're going to have to teach him. I think a good way of doing this is by slowly increasing the time he spends alone with them gradually. Eventually it may even get to the stage that they can stay over with him. I know this will be hard on you because you've always had your kids with you but I think it will also help your M in the long run.
The fact of the matter is that regardless of how things are going between the two of you, he has to start taking responsibility for his two wonderful children. When he starts appreciating them and enjoying them more, he'll see that they are something the OW can never offer. When he gets bitten by the parenting bug, nothing else will come close. Not his work, his OW or even you. The difference is that with you, your kids are something that you can very much enjoy together. IMO this can only bring you closer together as a couple.
As I've said before, I don't know your H so what I've written may be completely off the mark. By what you've said about him though, it sounds to me as though your H is just now beginning to discover the wonder of being a parent. Work on that and see where it takes you.
You're doing fantastic. Keep smiling.
Kev
Me: 32, Wife: 22 Son: 2 Married: 2 years Separated: January 5th 2009
Sometimes you have to become lost before you can find yourself.