Whoa there. You're wrong dude. There's no way he would have forgotten all of that. Even if he was a dick he couldn't have forgotten that just to be a bitch. I think in an earlier chapter it was mentioned that he had a near death experience that may have cause him amnesia. We have already seen from dohyun's perspective that he has attempted to remember but he simply can't. Sungho telling him that they had a sexual relationship, can only be seen as friends with benefits. So in actuality there's no way for dohyun to understand what is going on. If he can't remember the relationship he had with sungho it means nothing to him. You can't care about something/some one if you have no recollection of who they are or what went on .
Kurosaki, I agree... and I just had a thought.. wouldn't it be interesting, if he gets his memory back and remembers he loved Sungjo, but was taken away without being able to tell him. Then had an accident and forgot him?
Yo!!! that would be a really good plot twist. I'm rooting for your idea.
Dohyun is just a miserably vile person who doesn't treasure anything and anyone around him, he just takes life for granted. The fact the he can't remember his friend's faces and names and also forgot everything he did to Sungho is proof just how terrible he really is. It's like he just expects everything to come easy for him, he's just an arrogant bastard who will use anyone for his own gratification. I'm not saying he deserves to be raped but he does need a good kick in the balls!!!