I don't know that you need to blow up! But you can be firm. Set the boundaries for real.
Something like:
"Dan, when you have the kids, you need to show up at x:xx, and take them with you. Your visitation is not going to happen in my house. When it's time, you bring them back, get them in the door, and leave. You don't live here any more, and it isn't good for me or the kids for you to spend time here."
Stop engaging in his pity parties. "Dan, you brought this on yourself. If you need to talk about it, go hire a C. Goodbye!"
Etc., etc.
If you feel the need to get more anger out directly, you could mention OWs and all that crap, but I think you'd be better served to just set very firm boundaries. If you want to yell, though, I think your C would listen!
