I would address the finances quickly and calmly with her. Hell I even gave mine advance warning, to which she must have thought I didn't have the brass to do. I would then address the issue of joint accounts and what is who's there. Just do it with a nice calm casual, "well this is what you want so I wont stand in your way attitude". I know easier said than done, but, you still have a chance, I don't, I made these mistakes, so take them for what you will.
