Yes, it makes perfect sense. However, we could drive ourselves crazy by asking "what if" in all areas and situations in life. What if I had not said this or done that?
However, you probably know her better than anyone else....so you have to make that choice. But I will tell you like I told another young man who was staying for the sake of the child....in about 15 yrs that child will be out of the home and it will just be you and the W. Then what? Are you willing to toss the chances of a future with somebody you could be happy with? What about other possible children with another W some day? (BTW, the man I said this to...has a W that sounds like yours.)
Why can't you have a R with your child without her? I realize it's not the same, but when all is said and done....you have to make a decision or else ride the fense of "hoping she'll change"...from now on.
I think you are giving her signals that you are more than willing to work on the M if she would give it another chance. But, there's your problem....she's holding all the power in the R. She keeps you dangling at the end of the rope. Why not drop the dang rope, already? Dating, GAL, etc. doesn't mean you've dropped the rope emotionally....and she reads that loud and clear.
If you take the power over your own life and drop that .0001 percent of doubt, then she would fall all over herself trying to make you see just how "certain" she feels toward a MR with you.
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!