Maybe I missed something along the way.....but do you WANT her back home with you? I don't hear it when you talk about her coming back. It is like she chose this ONLY b/c things did not work out with OM and she saw him for the loser he was.....instead of seeing you, wanting you, and choosing you OVER the OM. I don't mean to burst your bubble, but I would just be leary about it. Something doesn't ring true here.
I am one that does not believe a peson falls out of love and goes to OP and then falls out of love and runs back to the first person. It takes time to get through the issues and the emotions, etc. Why doesn't she go somewhere else until you two have time to really work through your problems and see each other (like dating) for a while? Why does she have to move straight from his place to yours?
To me, it sounds as though you dread to see her come.....and perhaps with good reason. I hope you are not opening yourself for a lot more heartache due to unresolved issues. I certainly hope that she stays in C.
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!