why is he a jerk? for following his own feelings? for choosing to like who he wants to like?
Hyumwoo isn't a jerk tho, it is not his fault he likes yeona instead of subin.
In that case he has to stop hanging on Subin. What he does is cruel calling him and asks him to do some chores knowing his feelings. He knows Subin can't refuse his selfish request and because of that he can't move on to find another lover.
hyunwoo rejected subin multiple times already, it's subin who keeps holding on and pushing his feelings toward hyunwoo, it's annoyingly pathetic tbh. this is the reason why subin annoys the hell out of me, but I also find that trait of him endearing.
That's it! Nam Hyunwoo is a jerk. JERK. Now Subin, just give up on him and take your things so you can live in Hyung's appartment. There is no forgiveness for Nam Hyunwoo.