I remember my H wanting to hear me tell him that I would put forth effort in getting our M back on track. I felt so frazzled and so discourage.....and very unmotivated to work at a R with him. I hope you can try to realize that every day she is still there....she feels as though she is putting forth all the effort she can muster. I know that may not be enough, but it took me a good while before I could reach that place.
Don't know that I've said this to you or not, but I've told several that I had to get to the place of being willing "to be willing".....and that was a hard step for me. In fact, I think it had to be broken down into tiny baby-steps.
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!