. . .(Pearlharbr comes immediately to mind) were masters at positioning their "demands" as more of a "Hey, I don't know if *you* can be this person or not; I'm just telling you it's what *I* need. I totally understand if you don't think you can do this (I think Pearl actually went so far as to tell her wayward boyfriend that she didn't think he could!), . . .
I don't know if I'd recommend this with a wayward wife as much as I would with a wayward husband or boyfriend. There's someone about telling us guys that you don't think we have the chops to be able to do something difficult, that makes us want to rise to the challenge!