From what I read from the novel online where the translation wasn't official...
The main story end with them parting way because Kang Jun try to avoid Yohan until their graduation day.
They did meet at one point during the ceremony for the students who graduates but Kang Jun runs away and don't see him again until his university life began.
That's why they don't end up together in the main story.
There's a lot of side stories (as long as the main story) in which you follow Kang Jun in his university life but... Surprise... Yohan is his roommate in the dormitory and they're attending the same university ! Even though there's some twist and turns with how complicated and twisted both of them are...
They do end up together in the side stories.

Novel readers i need to know if they end up together or something. Yohan really hates gay people?