Been out of contact until now, sorry to hear about the current sitch, but sounds like you are dealing with it well.
Simple advice, focus on yourself and kids. Act as if you are having a great picnic and W can come (or not). Sounds like she still want cake (and your support), so the 'no can do's' are great.
Your doing great on the 'not reacting', makes them react every time you refuse to. Have a great weekend with the D's.
