Sorry - I've been purposely ambiguous about locations, for various reasons. I apologize if this causes confusion, but I still feel it necessary.
In this particular case, it hopefully suffices to say we live in state X, OM lives in state Y (although I suspect he's trying to move here), and W wants to fly to state Z (near where she grew up) on her bday. She wants to go somewhere that she has fond memories, away from here and away from family. Given what has been happening lately with her parents and other stresses (other than our R), I don't blame her. If not for the A, although I'd be upset she's leaving me and her daughters, I'd support her need to just get away. But, the situation is indeed otherwise. I basically told her that I understand, why I don't like it, but she makes her own decisions. I have a few other things I want to say, but will likely wait until our MC session next week to say them. No matter where we live or where she's going, OM has plenty of money (and apparently time) to meet up with her whereever she may be - where she plans to go for her bday weekend is no exception, and if anything easier than a number of other places.