Hi! and It sounds like this might be a bit much for Rufus. How old is this new puppy? Are you leaving Rufus and the puppy alone when you're not able to supervise?
Perhaps you could play some "look at that" games with Rufus. Put the puppy in another room behind a baby gate, or a sliding glass door...maybe even just in a kennel in the living room and encourage Rufus to first look at the puppy-every time he does he is rewarded. Then if you think that's not too stressful, only reward when he investigates a little closer to the puppy?