@Delilah After that...
Spoiler!
Jae Young also explains to him that he has been difficult to reach lately because he was looking for a solution for his departure to the US. In particular, he tried to put together an emergency transfer so that Sang Woo could leave with him, but he didn't succeed (Sang Woo's level in English isn't good enough and he must absolutely pass the TOEIC beforehand, that he doesn't have the time). So he tells him that he decided to stay in Korea, with his boyfriend. After all, his portfolio is good enough to allow him to find a job, even more so because their mobile game is a real success.
Suddenly, the solution of leaving for the US being found, they begin to go out together! \o/