Hi Shodan, first you have to protect yourself financially. Close the shared credit card. Yes, financial irresponsibility, even stealing is something I have seen in my sitch also.
I think you have the right idea about not letting your W go on the vacation at the cape. But I wouldn't mention what's "happening in NYC". Instead, I would say something along the lines of "I will not be with you on a vacation while you have made the choices you are making." Leave it vague and without any detail, and let her imagination fill in the details. Make this more about a boundary you are drawing, than about specific actions she did in NYC. I hope this helps.
