This has pretty much been going on since 2013. I think as long as she diggs in her heels and says she's not leaving......she's sure you will settle down and life goes on as it has previously. It seems to me it's time to do something different. Could you move out and take the kids with you? Could you leave her with the house, the car,.......and the payments? Find you and the kids another temporary place, and give her no spousal support, at least until you talk to the lawyer? Have you talked to the lawyer to see your options? Did you ever separate your finances and protect your savings, retirement, CC, etc.? I don't give a lot of legal advice b/c I don't have a lot of experience with it, and b/c it may vary from state to state/country. It doesn't mean you have to file if you get legal advice.
This comes as no surprise, and answers why she continued to refuse any sort of transparency.
In case you get another shot at R in the future, tuck this in your brain. Do NOT approach a WW who has just disrespected you in front of your children by telling her you are hurt! To a WW, it makes a man sound very weak to tell her she hurt him. She doesn't respect hurt feelings. She doesn't care. The only thing she will respect is seeing you stand firmly. Where were the boundaries? Where were your actions to enforce the boundary?
This woman has suffered no loss! She intends to keep her cushy lifestyle and her kids. Meet with your lawyer to see what his legal advice is.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!