DadsCB, I sort of think she is pursuing OM but it also sounds as though she is hurting about the family. It sounds as though OM is ending the A and she is pursuing while he is distancing. However, it sounds like in her thought process she is figuring staying with you if things can't move fwd with OM.
I certainly would not move D any faster unless you want D. I would also stay as detached as possible. Don't initiate contact and when in contact be friendly but not smothering.
Me 41 W 33 M 2013 Suspect A 11/15 Confirm A 1/16 She moved out 2/14/16 Stepson 13 Stepson 16