First off I want to say that I think you are doing great under your circumstances.
I think the problem you're having is when your reading DB and other situations you are not understanding the differences in the situations. I never have hid the fact that I think your W is the lowest of the low of WWs. The disrespect she has shown you over the last year is despicable. You can't be accepting these invites into her house for a drink or invites to BFFs apartment.
Convos about kids and finances nothing else.
I am going to suggest to you that before you go to the final ultimatum that you try some tough love first.
Start with giving her two weeks to get her horse off your property. Start with " W I've been thinking about it and this arrangement isn't working for me anymore".
of course if you decide to go ultimatum run the scenario by the board. N
