Ah. Yes that's makes things a bit difficult. You don't want to be controlling and punitive as sandi mentioned when it comes to finances.
Where is she sleeping? Perhaps nudging her out of the MB is a start? Treat it as an in home separation.
34, xw33 M-10, T-18 2D (8 and 5) Ilybinilwy-1/16 EA/PA- 7/15-present (with my former best friend) Trial apartment-2/16 (also when she considers us separated) W moved out-8/16 W Filed 11/21/16 D final 1/30/17