Update- So this morning was a nightmare. All 4 kids basically had a meltdown. S14 was the worst. I wound up keeping them home from school and contacting their IC. Basically, we talked through some things. S14 is having issues with H not calling or spending time with him.

At one point - I did call H and say hey this is what's going on, I am taking them to IC and may need you later. So after everything was said and done I called H. He is still stewing and fuming at me. To the point I really can't have a normal conversation. When I called I was in town and knew I would be driving past his house. I said would you rather do this on the phone or in person? I can stop by there or meet you somewhere. His response "Why in the world would I want to do it in person? How many times have I gone to jail because of you?" In a nutshell, the first time he left back in 06 we did get in an altercation and both of us went to jail.
Charges were later dropped. Basically, it was to give us a cooling off period.
So I said 1 time. You are right. However, I think I was actually in jail longer than you. So he snidely says "well see there you go, I guess that makes it alright then. I don't have to worry about it." We sort of went back and forth. He claims he is not visiting or calling them so that he can avoid me. Which honestly I feel like that is a cop out. One time when he called he and I did get into it. I stated that. You are right one time we did have an argument. I can understand why you might be afraid of that. I factually stated at this point. If you would like to have a relationship and to see your children you need to do so now. S14 in particular has stated this is a problem for him. He wants to see you. I also stated quite plainly that I was not saying it to try to manipulate, control, or cause guilt. My only motivation was the kids. And frankly, although I do have a huge problem with him and how he has handled things, my primary concern is the kids and how they are coping. Obviously, they are not doing well if this morning is any indication.
One of the things with S14, he is starting to blame me. I think he feels I should be able to "fix" things. He and I have an exceptionally close relationship. However, he has not been willing to open up to me about his feelings concerning H and I separation. At one point he did say though he thought we were better off without H. Just because we are no longer dealing with the anger and outbursts. I am actually controlling my anger a bit better but I still need work. Anyway, back to H. He just continued to remain confrontational, nasty, and rude. Then at one point, I started to get drawn in and he had his Aha moment. You know what I mean? His validation that I am the one that is angry and arguing. I am the cause of all his problems. I did say that I had been trying to avoid him so as to not have an argument with him. Just like having D12 answer the phone the other day. I also called him on the fact that he was asking who was in my car, that it was none of his business. He claimed he knew it was her. I am like 95% certain he didn't. Whatever. So I took a moment. Calmed down and just hung up. I can say this much though, he has been stewing and mad at me for days now. I can tell by his voice that he is in full blown fury. He has sounded that way since I talked to him on Monday or whatever day it was. Maybe Tuesday. It's all starting to blend together. But it has been several days. I did say I am not certain what I have done or what you think I have done to make you angry. I do not know of anything new. I have repeatedly apologized for my actions in the past. I would love to try to make amends but, up to this point you have not been open to that. I said that midway through the conversation or something. Before his aha moment.

My perception is he is trying to bait me and continue his pattern. He is looking for his validation that I haven't changed or am not changing fast enough. Does that make sense? I suspect he is having lots of guilt and he is trying to justify his behavior. Not sure. I shouldn't try to mind read but it just fits are pattern. I wonder how long he will stew if I don't give him the fight? He is coming over this afternoon. Stated he will be here when the kids get off the bus and will take S14 to his friends to get ready to go dress up for trick or treat that is supposed to happen @ 5 pm.

How should I try to handle him? Should I go out of my way to avoid him or should I act as if and go about doing my normal stuff?
How can I verbalize my boundary of not fighting? Do I just say that like I did before? I am not fighting or arguing with you? It worked well but really enraged him.
Anyone got tips for helping me keep my cool when all I want to do is scratch his eyes out and beat him with a pan? Throw shoes at him. Hit with a broom, Throw rocks. Hurl insults. In a nutshell, hurt him back. You get the idea. Make him bleed. Why am I like that? It feels so primal and inhumane. I dunno. Suggestions are welcome.
Hope everyone here is having a better day than I.