I simply would suggest that you stop offering her so much leeway. The way to do that is to detach.
Your W is a grown woman and she is more than aware of the fact that she has two young children and has parenting responsibilities to uphold. Yet she comes home from work when she pleases, you internally fume about it then spend the rest of the night thinking of ways to reach out to her or put a ton of energy into looking for a clue on why she acted how she did.
She opted not to participate in booking a cabin for the ski trip yet once you chose something she was not happy. Well, she had the opportunity to be a part of the planning and she opted NOT to take part. Her consequence? You changed the reservation so she got what she wanted.
Why would she change? When she does something you don't like you don't really set boundaries.
She doesn't even respect you enough to be where she is supposed to be when she says she is going to be there yet instead of setting a boundary about that you spend the night trying to talk her LL. Boundaries, mutual respect and detachment MUST come first or any gesture to talk her LL will a total waste of time.
You fear losing her but really, what have you got to lose at this point? She treats you like a roommate and has really put her responsibilities at home on the back burner. And so far you have not indicated to her that you are not okay living that sort of life.
If you had a co-worker that showed up late all the time, didn't do what his job entails, didn't show you respect and basically did as they pleased would you reward that behavior with "private office talks about personal stuff" and trying to connect with them on a deeper level? I doubt it.
You keep trying to connect with your W on a deeper level but until some healthy boundaries are set and some respect is regained I don't feel that will ever happen.
