You need to change your attitude about this. I know it is hard, but you need to learn to take joy in the fact that your son is bonding with his dad too. Nothing is more joyful than a baby reaching out for you. Think of all the times in his life when he reached for you, and now think about your husband's joy when that baby is reaching out for him.
Throughout his life he will have times when he seems closer to you and times when he seems closer to dad. It seems to go in cycles and they are very healthy cycles. So this is the first of many. By reaching out to dad your son is becoming more independent; he is learning that dad is an important constant in his life who loves him as much as mom; and he is exploring his options. He will come back to you, then go through another dad phase.
You cannot take this personally or raising your baby will be a roller coaster ride. You have to take pleasure in the fact that your baby is normal and is able to form bonds with others. When your baby says when you reach for him, "NO! Daddy!" instead of getting upset, view it as a little bit of free time. Say to your husband, "You win again!" and go read a book or do something you've missed doing.
A baby's smile, love and attention is a bit like winning the lottery. Take pleasure when your husband wins instead of taking it as a personal rejection.
VickiS