yogagirl I have a somewhat similar situation. stbxah gets angry at the entire world, holds it in until he is going to explode and then intead of talking to the people who may have caused his feelings and get some resolution he used/uses me and the kids as his whipping boys. stbxah though is in no way dry however he does share the characteristic of not taking responsibility for any of his behavior. It is always someone else's fault he acts the way he does. When I stopped taking the abuse he needed a new target and he selected our 9 year old son (who has mental health issues)-that is when I left.
No one should have to be the can in which they toss all their garbage-active or inactive in their drinking.
I got sucked back in recently. Until then my boundaries had been pretty good. But he back-doored me by using the kids to send messages--and it worked. But thanks to this great place, instead of staying and stewing like I have done in the past (or staying, stewing and then ignoring it and pretending like it did not matter) and let it go, restablished my boundaries and am trying to help my kids set boundaries as best they can at 5 and 9 years of age. I also went back to taking care of me-going back to that old adage that if you don't take care of you, you are not really fit to take care of others (not that I think you should be taking care of him AT ALL).
It is amazing how fast they can change their behavior when they think their enabler is going away emotionally or physically. It is equally amazing how they return to their previous bad behavior once we make ourselves available to them agian.
Welcome--I have learned a lot about myself here and am starting to heal because of it.