A Looking on the bright side, your baby is a smart little guy. He has already identified your loving arms, and any of your other available appendages for that matter, as the center of his universe. As far as he's concerned, there is no good reason to leave Mother Earth. Unfortunately, this leaves your husband lost in space.
My babies all did the same thing to my husband at one time or another. No matter how much love and attention he gave them, if I was in sight, they treated him like they treated their diapers. He wasn't the only lonely daddy, of course. All of my friends report variations on this theme. One dad I know used to come home from a long day at work to see his toddler standing at the door shouting "You doe way, Daddy! Only Mommy and me!"
The heartbreak he felt was irrefutable. It was not, however, irreversible. The way he snapped back into his baby's orbit was to fiddle with time and space. Specifically, making sure that Daddy got time with Baby, and Baby got space from Mommy.
How can you do this? It's as easy - and as difficult - as giving your baby to his father and walking away. Quickly. You can expect much wailing and gnashing of teeth. And your baby won't be happy either. Rest assured it doesn't last forever, and you can take some comfort in knowing that this father and son bonding time will help both of them develop the coping tools they need to get along with each other and without you.
In the meantime, I would start taking notes about which of those coping tools work the best, because at some point Daddy will be the parent of choice and you'll be the one searching for signs of intelligent life in your universe.