Might you consider setting a boundary on this NDY? Letting her know that you regret the recent discussion was seen by him and he was upset. Letting her know that you don't intend having any further such discussions if he is present. And if she begins one, calmly tell her - we can continue this discussion at another time when we are alone.

If she continues despite this - calmly remind her of the boundary and then walk away. It takes two to engage, and if you just remove yourself calmly, she'll have to argue with herself.

I hate to think of children being impacted in this way, and I agree with you - it's so important to try and support him through this. SS's mum had a volatile R with a boyfriend, and SS used to get sent upstairs during arguments. He told us he would sit in his room feeling scared and wondering if he should try and help his Mum. He was a similar age to your little guy.

T 13 M 7
Me 48 H 46
SS 15
BD 7.14 PA
D final 5.16 (H filed)

We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus