Fucking exactly. It's more likely that expressing emotion for another human involves risk and vulnerability. It's not "logic," although that's a popular excuse these days. Animals are safe. Therefore if you want to trick yourself into being more affectionate, just play a mind game where your girlfriend is as safe as your dog.

The likelihood that OP treats his girlfriend exactly like his dog is nil. His girlfriend doesn't get walked, he doesn't throw her treats, he doesn't tell her to sit before she gets a present, her present isn't food, they don't play tug o' war, she doesn't get belly rubs. He's just hacking himself into being more comfortable showing affection to a human being. If he feels better thinking he's treating a human being like an animal, hey whatever works. I just hope she doesn't ever hear that.