I feel for you, this sort of thing and IHS is really hard. Stay strong. It does get better, and her behaviour will ease up.
One thing I found that helps is mindfulness. Every time I know I'm entering a room with STBXW, I mentally prepare myself to be aware, focus on any conversation, and not let her get to me. It doesn't work all the time, I do forget. But it means I'm ready for any bad behaviour or attempted fights. I've seen a notable reduction compared to just after BD.
I also mediate, but that is something I've done long before BD1 and BD2. If I don't, I can't regulate my emotions.
