I find with Jarvis that he has a special relationship with every person that he sees on a regular basis. And he has different uses for each person.
At the moment i'm very pregnant and so not doing every walk with Jarvis like i used to, so his daddy has taken over the walkies/playtime role, however, this means my role in Jarvis' life is cudddddles,cuddles, and more cuddles!
He also has his granny who's sole purpose is to let him out into the garden when he doesn't need a pee as she's a soft touch.
And he has his auntie who is just for fiesty games.
I don't think you need to worry, puppies manage to adore lots of people equally. I've not got a cat but i've known of lots that are one-owner animals, and they are generally a lot more independant.
Milo will find out who's best for getting his own way with what
and will adore you both the same i'm sure.