We say that when a guy opens a door for a girl, walks close to the road, or puts his jacket on a puddle for the girl, he is being chivalrous. But that’s not necessarily chivalry.
Chivalry was pretty much admiring from a distance, that’s the difference from today. Today we do things with our girlfriend/boyfriend which is kind of an ownership type of thing. The past was different. The knight admired the princess, who was already to be wed to some king. The knights always knew that they would never become a ‘thing’ (I think knights were supposed to be ‘chaste’ as well), but they showered the princess with gifts and admiration anyway. Why? Because making them happy was enough (I would guess), they didnt feel the need to ‘own’ the princess. Her happiness made him happy