The one thing about detachment is you want to detach emotionally, but it doesn't necessarily need to be physical. There is a difference between the two. Being able to be around you husband physically and being a good friend, not showing any blame and just having a relaxed good time together as a family is powerful. Sex can be powerful too, of course. The trick with detachment is to emotionally detach...
If he wants to be involved I would let him. I'd be nice and thankful, but not expect much more else. Live your life as if he's a friend. Make sure the times you are together are good ones so he has positive images of you, the kids and his family to hold in his head. Even when they do something crummy it isn't worth blaming or creating bad memories. Never take anything personal. Just be independent and happy in yourself. It's hard to know what his motives for involvement are, but don't worry about it. Just have fun and enjoy yourself. There are nice things about not having them around. You get the whole bed to yourself... you can buy new clothes without having to sneak them in when H isn't home... you can make peanut butter and jelly sandwiches with Campbell's Chicken and Rice soup for dinner and everyone in the house is happy with it...
That isn't saying you wouldn't choose your marriage and having your family together first, but sometimes there are silver linings...
There is no arriving, ever. It is all a continual becoming.
