Dropping the rope is crucial. See after some time these wayward spouses are getting off and building up esteem on your reaction, your pain and suffering, your asking them when they are coming home, your beggging etc.
Your filling them with a selfish pride by holding onto it.
Well speaking as one of "these wayward spouses", I don't agree. That was not at all the case with me!
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!