This is just poorly thought out. You offer dessert and to pay, then classify it as food motivation. I mean it could be that he's happy you're paying, or happy you want to be out longer. If anything, he just ate, so food motivation would be at its lowest.
You're taking an animal that isn't as complex as humans or even has a concept of society, and trying to apply that to a person in a relationship. I think the thought is there, but the conclusions are a bit flawed.