You know, as Puppy explains it, "Leave them alone, and they'll come home..." instead of being proactive right away; even if that means losing your cool for a moment, asking them "why?" exposing A's, etc.
I'm not talking about groveling, begging, stalking, or other weak, needy, unseemly, and other unattractive behavior. I'm talking about righteous indignation. I'm talking about snooping, fighting dirty, arming yourself with intel, etc.
It is my belief that Bo Peep doesn't work because it is cake-eating, right from the get-go. "I'm here if you want me.....when you're finished exploring.....see how spotless the house is.......see how I have all your favorite food in the fridge......see how wonderful and understanding I am....I'm the better option.... "
Are you really thinking that they view you as the better option? I think not. You are the default position until they decide to betray you again. And they will. And it will be easier the next time because they already crossed the line with you once. And since you were "so patient and understanding" the first time, there were no consequences.