Si-eon's tendency to "give"

So, I previously thought that he was in a relationship where someone used him, and he was hurt, so he distances himself emotionally now. However, he seemed to sincerely resonate with Namwoo's sister when she spoke of how she lost her sense of self because she spent so much time taking care of Namwoo growing up. So, maybe he was in a similar situation, and he only received validation or attention when he was taking care of that person. He started fidgeting when she asked him about HIS motivations, but he's never done anything for himself and he's become so comfortable with only doing things for others that he's probably never really thought about those things, so he got nervous. When he talks about doing things for others, he's told things like he's "humble," and "giving," so he likely feels empty, but validated. Could he change his way of thinking? Probably, with the help of others, that truly want to help him, and his own will to do so. Again though, he's comfortable with this way that he thinks and does things, as explained by his conversation with Namwoo. Namwoo talks about getting used to "all these changes," and Si-eon mentions that it's easier to stay on the same path (I belive because he said it was easier, or something to that effect.) Anyhow, I think Namwoo could affect some change in him, but it's gonna take time.