I think they have one person they consider a favorite, but will consider capable substitutes when necessary.
Diva loves hanging with my DH, but when we come home or when I come home, she's all about me. She is my shadow. She follows me when I'm getting ready for work. She'll come and sit on my feet or between my legs when I'm brushing my teeth or applying my eyeshadow. She'll even come over and try to lick my lotion (never does that with DH).
When her tummy's upset, she runs to me. If I'm in bed she's there with me. If DH's in bed, she might go and lay down with him for a bit, but she's always right back by my side.
She's my dog - has been since I got her.