
That's the point. It was necessary for Lee Seodan to understand that this will come up again. While he has made it very clear about what happened and what he feels about him at the moment, unless Lee Seodan himself overcome his insecurities on his own they will keep having the same conversation when new issue rises. In the novel chapters ahead, same thing happened, he was bothered by his insecurities the only difference is, Lee Seodan spoken out about it FOR HIMSELF. Seriously I can't explain this if you're unable to see why he needs to say this.
I can't stress enough the story isn't about some cliche relationship where characters are acting fluffy, romantic, gentle etc.
“if you’re hoping that i fell for you at first sight, that’s not the case” that was so unecesary, what the bottom said had no correlation to that