K, I lost track of what exactly you wanted to talk to him about without the kids present? And its not clear what you really want - in or out?
You will have to find a way of communicating and problem solving that actually works. Demanding does not work, asking might. YOU will have to take the lead to change the dynamic to one that has a better likely hood of working and allows you to still keep your dignity if it fails or if he voices anger.
You can tell him you are disappointed by his change in plans (if that was indeed the case). Your leaving the house will not really solve anything regardless of what clear message it sends. Better would be to arrange for someone to come over and babysit when he shows up so you both can take a walk and talk things over.
I realize its hard to think on your feet and solve these sorts of problems when they hit you in the face but you know him well enough by now to predict these things. Remember he is probably hurting also from your perceived behavior towards him (as he sees it you are the "meanest person in the world" so he seems to be avoiding you).
