Are you willing to share any details about the coparenting agreement issue?
I am going through a lot of similar issues right now. It feels like peeling a whole new layer of the onion away -- first it was trust in my life partner as a spouse, now it is trust in her as parent. And in the same way I held out hope she would want to work on the MR for the sake of our kids, I held onto that same hope about our ability to co-parent. It is almost as hard to go through this process of realizing that we can't have the happy amicable D where we support our kids in the most healthy way possible (at least for now).
It sounds like you are right to feel angry, but be cautious about that anger feeding into an escalating cycle. I'm not sure you need to hand him the rest of his belongings ASAP, but you can address the issue at hand and make it clear how it has affected your trust in him as a parent.
