Hi D.,
I can understand how this upsetting this situation must be for you. However, I will say that it doesn't sound all that unusual to me because Mothers and Fathers bond differently with the children. In my experience, my husband had an easier time with both of my children as they got older. He was a very hands on Dad (for the most part) with my oldest and seemed to prefer the oldest child once my second was born. It is pretty safe to say that I took it a little personal. My hubby was a very good Dad to the baby...but seemed more comfortable with the oldest.
It sounds like the two of you have a beautiful family. I would suggest that you let nature take it's course with your hubby and children.
You did not indicate that your hubby isn't nurturing, feeding, bathing the new baby AT ALL...so maybe he needs more time adjusting to caring for two children. Try to remember that you have had nine months or so to care for two. He is just getting started.
Congrats on your new little one! Everything will work out. Relax and enjoy all three of them. This too shall pass! :-)
Wishing You Well,
M.