Sounds like there was alot of stress going on in the beginning that maybe has worn everybody down now.

His kids may not be model kids, but reading your original post, I really feel for them. I dont know your husbands history as in his activeness in actual care (physical/emotional) of the kids while with his ex. You state that "he had no choice" in having his kids as CP like it was an unwanted thing on his part. Maybe it was difficult instead, if he and the kids werent use to depending on each other and then were all of a sudden thrown into a situation where they were all they had. I can only imagine what his older kids have gone through emotionally on their own knowing that their mother just up and left them and then becoming a part of a family where there are younger kids involved. I think the older they are, the harder it may be for them to adjust if they ever do while in the home. Younger children take up/need more time in taking care of them and the older ones tend to be left out or at least they feel that way. I can only imagine. Being older, their ways of venting may have been rebelling against the rules. It sounds like they were miserable having gone through what they did. Then yours are small. Thats alot to deal with. It seems he was not this way in the beginning of the marriage or you would not have married him, so I assume this has happened over time. Not that it was a bad choice to be together mind you, but I can see why there was/is conflict.

He shouldnt make the kids feel they are walking on eggshells, but maybe he hasnt dealt with his past completely or unable to, possibly has strained relationships between he and his children, I assume he is working full time, is dealing with the beginning of "empty nest" while still trying to be a father to young ones........and all this combined comes out on the ones there in the home. It does not justify it, but it could be some of the reasons.

I just think when you marry someone with children, regardless of how difficult it may be, that you stand by them. Im not saying that you two are not doing this. Maybe you two have hit a point where you have done all you are capable of doing on your own. Joining two families is something we take up as a responsibility when we decide to walk down that isle. We marry the spouse AND kids. Its never easy, but I hope somehow all of you (parents and all kids) can work this out to keep another family from breaking down. Counseling for everyone could help.

I know there are lines you cant just cross or allow to happen, but I hope this can be worked out by both sides walking in each other's shoes a while to maybe see where the conflict is rooted.

Good luck