While it's certainly an interesting tact to have her just...never really caring about her own wants because she sees how giving in to others makes them happy and that in turn makes her satisfied, I'm not sure where the author is going with this. It certainly makes the MC seem like a decent guy because he realized a relationship built on one person's wants is never gonna work. So getting her to think about herself shows he actually cares about her beyond things others wanted from her.
He's not really a strange guy, he's just strange to her cause no one really cared about her before, not really. It's outside of her experiences.