This is contempt. Hate is a completely different emotion.
I am not sure you distinquish the two. It would be helpful if you did- I think so.
Why?
Well if your feeling is contempt, the two finger salute is dismissive. It makes you feel better so go ahead. You can swish the behaviour out of your space and back to her.
And you can separate the behaviour from the person. Feel disgusted by her behaviour and not by her then there won't be leakage in your body language near the kids.
I think it would help you to say to yourself , disgusting behaviour, how low can you go WW. Without being disgusted with W or angry at her.
You can say, "not a nice way to behave" and "charming" and "really!". Whilst grinning like a Cheshire cat and up yours.
Oh and OM is a sleaze ball, lots of two finger salutes. Grot bag, scum features and pond slime.
V
Freedom is just another word for nothing left to loose. V 64, WAW