I don´t get it anymore could somebody explain it to me?

What I *think* now, is the guy that Hajin went to the school with is the guy he is dating now.. He overheard that conversation and prob. split and when he sees Hajin again,he pretends to be his brother so he can be with Hajin again without dealing with why did he split with no word. Now Hajin is meeting who he thought he went to school with but sees it isn't, so he's figured out the guy he is dating has been faking his identity all this time.

Hi, so basically Hajin went to school with Hangyum(the idol) but at the beginning of this manga Hangyum(the idol)pretended as If he wasn’t the Hangyum from high school when Hajin asked him. So he pretends as if he isn’t the Hangyum from high school and tells Hajin that his brother ”Hanwool”(the one from the lunch scene just now) was actually Hangyum (from high school. It was easy for Hangyum( the idol) to act as if he was someone else because his brother(Hanwool)was living abroad. But his brother suddenly came back so Hangyum persuaded his brother Hanwool to ACT as if he is Hangyum from high school.We never knew why Hangyum(the idol) pretends as if he isn’t the Hangyum from high school. But in this episode it became clear that he probably pretends to be somebody else because he thinks hajin hates him (The Hangyum from high school). 2. The guy with brown hair is his old fling/ boyfriend if I remember correctly, you can go back a couple of episodes to check. 3. Hajin’s first love is Hangyum. he is in a relationship with him right now, you can say that they found each other again after a couple of years because in high school they already had “a thing” But as you can see in the flashback from ep.39 that didn’t end well.
I tried to explain it as easy as possible. Hope you figure it out!(๑•ㅂ•)و✧

Same

holy crap i was so confused but you made everything so easy to understand, thank you T_T

Thanks!

Thanks a lot! I get it now! :)