Venice,
I was exactely in your shoes 2 years ago when I left AH. He sent me a very professional email to let me know that
1- he was not moving out
2- the house was the kids' house and therefore, there was no way they were moving out.
3- I was the one with a problem, therefore, I was the one who had to move out.
He threatened to get a guy quite influencial in local politics as his lawyer to back his case. He threatened all kinds of things.
In the end, I just told him I was leaving WITH the kids, and he didn't do anything to stop me which really surprised me a bit. But in hindsight, he probably still had hope I would come back so his manipulation for once played in my favour. Now, 2 years later, after he saw I wasn't coming back, he went to a pseudo rehab, still smokes pot, drinks "occasionally". And all the hard work is about to start to finalise the divorce proceedings....
It's all so hard but anyway, I am accumulating hard core evidence that the guy is not fit to have a 50/50 cistody arrangment in place.