So sorry you find yourself here but, you are in good company. You will find a lot of help here.
That was a very abrupt departure. I haven't read a situation like this one before so perhaps some who has experience with this will chime in.
As far as financial legal matters, talk to an attorney. she makes more than you so she may have to pay you. She may be asking for the moon so that she can have some negotiating power. You need to seek an attorney to protect yourself. Even if you just consult with one to see what your rights and obligations are.
Financial problems account for a great many D's. My situation is partially rooted in financial problems. What ever happened to "for richer or poorer", "for better of worse". Its a nice sentiment until one person breaks the commitment.
My wife said she is filing for D too. She hasn't said when but it seems inevitable at this point. Very sad when marriages/families fall apart.
Read Sandi's 37 rules, the book DR and DB and read as much on here as you can so you can understand what is happening.
This is not your fault, but it is your problem. Work on yourself for now. Eat Exercise Sleep and if you cant sleep, REST.
Take care of yourself first then worry about her. It will take some practice to get the PMA and GAL activities going but, DO THEM! Start today not tomorrow. This forum is here so that you can improve yourself, not your S. Your S may see your improvements and and question her decision. Keep in mind that you are doing these improvements for you right now. Focus on you.
Keep posting. There are far more experienced people her than I that can help you. Just keep learning about what MLC/WAS. The more you understand what it is, the better it will help you cope with the emotions you may be experiencing now. It helped me quite a bit and still does. Start MC too if you think it will help you. Go by yourself.
Once again, you have a great resource here, USE IT!
