When you introduce him to your new furbaby, sometimes it is better to do it outside, or somewhere else. He won't be so defensive of his house. After he gets to sniff and get acquainted he will be more willing to let the newcomer in. It sounds like you will have to give him some extra attention at first. The new puppy won't mind, she is used to sharing her mommy with litter mates; but your boy hasn't had to share for a while. Good luck, it will be fine in time I know.
