If the drama starts, walk away, don't listen, don't respond. i know it's easy to say but such a release when you can do it and walk away.
Stay strong and good luck. Husband will come around or he won't. But your son will know that you stood up for him.
I am trying to do that now with my dil. when we can't visit or they won't visit - oh well, their loss. things seem to be better for me when i gave up the hand wringing and wishing for what i envisioned with my grandchildren. When we see them we enjoy every minute and they do too. We have moved into visits with my son and the kids without dil. Love her, but it is much calmer without her watching us every minute and always in control. Life moves forward and i try to keep the drama away.