So far, 6 months after I moved out, STBXAH and I are getting along fairly well. He has not been outright abusive to me, and I'm generally good at ignoring his run-of-the-mill ridiculousness. We have our moments, but so far, things are certainly cordial and cooperative where our DS is concerned.
I don't know if we will be true friends long-term, but 99% of the ugliness and contentiousness of our relationship is on hiatus for now, at least. That said, I do not take anything for granted where an A is concerned. As long as he's not sober and in recovery, he will get worse. And who knows how that will manifest itself.