I don't think you should have a sit down with OM's W. Things are quickly turning south and you see what your W is capable of doing. Apparently, she is telling OM lies about you, which as Sara said, is not uncommon in a WW.

Protect your finances ASAP. Get legal advice.

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!