H - I will respond more fully later. It is awkward sometimes because we hide so much from each other - lots of emotions boiling away underneath the surface.
I will say, as hard as it will be, to not let her set the temperature in the room. Pleasant but not forthcoming. If she starts a conversation, engage pleasantly but keep things at a superficial level. Don’t start conversations yourself unless it’s logistical or practical. Don’t ask questions about what she’s been up to. If she asks you, tell the truth but don’t over share. This is about the kids not you or her so keep the passive aggressiveness and sarcasm to yourself (as much as you’ll want to say it). If she is sarcastic or passive aggressive then change the topic or calmly leave the room. Do not take the bait. Can’t temember who it was (AnotherStander or Ready2Change I think) who use to psych himself up before coming home (like football players do before a game) by punching the air and saying something like “I got this”.
Many times you will want to go in your room, shut the door and cry or scream. It is ok to do this - you are human and it [censored]. If you need to post, vent or cry here - someone will always be listening.