Frank, that makes sense. They have to go resolve themselves, and the LBS has to give them space to do that rather than pressure not to (that chances are they'd only resist anyway)... though I don't understand why it's to be presented in the form of a letter. I get the feeling these relationship-gurus used to be English teachers.
I think you're correct too that it's not delivered as an ultimatum that may burn bridges, but maybe more like a, "honey, I understand you have to do what you have to, and I love you, and I'm here and I'd prefer you be with me, so do what you have to do but you and I know that I won't wait around for ever" type of thing.