Aww your post breaks my heart. Who is the primary care giver? Do you feed him? At 4 months their attention span is still very short, and they go through a lot of "stages" of development. My guess is this is one of those stages. Our dogs will readily go to anyone in the house, but when I am home, they prefer to be by my side, but I am the one they depend on for their basic needs most. I will say though, that it was well over 1 year before either one of them really settled in and attached to me. Don't give up. But if he doesn't change my only suggestion would be that your hubby has to go!
jk.....