It’s bc he treated Yoon like shit. Ya it’s understandable to be with someone else after waiting four Years. (Bc he has been with the new guy for a year).
I totally understand moving onto someone else, especially if you think your lover is dead. What I’m mad about is how he acted maliciously to Yoon.
Obviously he felt he needed to be loyal to his new man.. but you can’t just tell your past lover who you thought was dead that their “just someone you know”. He could’ve let Yoon down easy but instead he made Yoon feel even more heartbroken. :(

finally yoon said sorry to taejoo ;;;;;; idk why people hate taejoo when what he did really rational