Wow - Optimust / I am somewhat new here but having the Ds in the middle of this appears to me to be a recipe for disaster.
Maybe I'm not an expert here - but ultimately I think your reaction(s) will dictate to the girls who they can count on. If OM is inevitable, then your demonstration of respectful space will demonstrate to your girls that you are the source of strength in the chaotic world their mother is creating. Ultimately that's what kids their ages need and will rely on.
I can't imagine how difficult and hurtful the presence of the OM is to you - but your higher calling is as a father.
Hope you don't find this offensive.
M-48/XH-48 M=25/T=28 years Ds-24,22/S-18 D - 3/11 A Day at a Time