My girlfriend has a dog He is 5 years old We can not understand why when I'm with him he changes the behavior. If I take the little one and put it on top of me with my belly towards the ceiling. He is calm and easily falls asleep, but my girl does the same and I am not at home, she does not want that position. And he becomes more loving when I'm at home, but when I'm not there, he's more independent. She is very good with the dog and trained him very well. But with me it is the most relaxed dog. In fact, I correct it more strongly when it behaves badly more than my girl. How is it possible for the behavior to change depending on whether I'm there or not?
Dogs are intelligent and can have different relationships with different individuals. This dog likes you a lot, and probably respects you, since he accepts your discipline. It doesn't mean the dog doesn't like your GF: imagine a kid that behaves like an angel at school, but is a devil with his mom, it's just different relationships and emotional politics. Dogs might behave differently with men vs with women also. Maybe your girlfriend is less attentive and the dog might not feel as confortable to sleep on her belly, for example afraid that she will roll over him.