Both are equally to blame here

and they're both hurting, that's for sure. As I've said before, they're both entitled to and have every right to want the relationship to be how they want it, whether it's to stay in the closet or become public. Neither are wrong for expressing their needs. What they both need to reflect on is what kind of comprise they're willing to make to make things work, because you don't always get what you want in a relationship, and in life in general. Love and affection, or physical chemistry, by itself can never sustain a relationship. It takes commitment, communication, comprise, and intentionality every day, to keep a relationship going. The biggest problem I see between these two is that neither of them is able to see things from their partner's perspective, and nor have they made the right efforts to communicate their perspectives to each other properly. So in my opinion, being apart is exactly what they need in order to have the time and space to reflect on their actions and lack of communication and understanding. Garam demanded space, and took actions accordingly without consulting with his partner. Left the house and got himself a single room. Jaehyuk saw the physical toll it was taking on Garam and recognized the severity of their situation, so he told Garam he won't bother him anymore because he sees himself as the cause. Garam got what he asked for. People deal with getting hurt differently. If Jaehyuk thought going abroad was the best solution for him, then I honestly can't blame him too much. He may have even thought that it was what was best for Garam. Otherwise, they were bound to run into each other somewhere at the university. So he removed himself completely and got rid of all possibilities of an encounter. Do I personally think it's extreme? maybe. But I also know that people do extreme things when they're hurt. It doesn't make it right, but I can at least understand. He also obviously didn't go abroad to spite Garam out of any malicious intent or anything like that. I'm sure he's hurting just as much. And I hope that they both take this time to emotionally grow and mature a bit more.
I'm personally okay with this development, and I'm really curious to see where the author is gonna take it from here.