I DIDN'T UNDERSTAND PLEASE EXPLAIN ME I'M REALLY LOST THERE
1- Woojin and Hwon met when they were kids and Hwon immediately feel in love with Woojin and would do anything for him. They start a relationship more in the style of pet/owner. In Woojin's own words: he was always a thoughtless kid whose only goal was to have fun. Also he defines himself as someone who lives to make planks out of boredom. Woojin is also someone that, despite not being abused, has very cold and indifferent parents so, besides his childhood friend and his sister, no one else really shows affection to him. Hwon, from what we know, doesn't have any easier. He seems to be a neglected child, wearing dirty clothes and being raised by an aunt that is only interested in the money she gets by raising Hwon. He probably sees the attention that Woojin gives to him as the most precious thing he ever had what could explain his total devotion to the boy.
Note that, despite having feelings for Hwon, Woojin looks down on him because he thinks his devotion and blind love for him makes him pathetic, a pushover and a loser ( his words in the manga) and he enjoys using the other's guy devotion for his own entertainment. This is a pattern that they repeat when they meet again even tough Woojin doesn't know they are the same person.
2- Still as kids, out of boredom, and by Woojin's idea, they start messing around with this homeless kid. One day the homeless kid takes Woojin to an abandoned place and tries to make a move on him. We don't know if his intentions was to rape Woojin or if Woojin was okay with it ( it's possible since apparently Woojin never shows to be faithful to anyone) . Anyway Hwon shows up and protects Woojin by placing himself in confrontation with the other kid. When they were leaving, the beggar hits Hwon with a bat and the last image Woojin sees before running away and saving himself is Hwon stretching his arm to get out of the barn and calling out for Woojin's name.
3- Woojin runs away and for fear of getting himself in trouble, decides not to tell anyone. At the same day his sister commits suicide and even after going back to school after the funeral and not seeing Hwon there or hearing from him, he still make no effort to look for him or tell anyone. In other words, he just left his friend to die alone in that barn after he had risked himself to save Woojin. His family moves away soon after and we get to meet Woojin as an adult and his mysterious new pet -- Hwon who is again someone who loves Woojin and a way of entertainment for Woojin.
4- Either out of shame or guilt, apparently adult Woojin has erased from memory the events with his childhood friend but his relationship with Hwon brings back his memory and Woojin begin to suspect that Hwon and his childhood friend are the same person. He mentions this to his adoptive brother. The brother goes on investigate what might have happened to Woojin's childhood friend and reports back to Woojin that everything indicated that the boy had died. There were no records of him and his aunt had collected insurance. Woojin then starts to believe Hwon could be the homeless kid who tracked him down.
5- The relationship between Woojin and his brother is never clearly explained but apparently Woojin was attracted to his brother when they first met and his brother took advantage of this by playing games with him and leading him on or humiliating him. It's not clear if they ever slept together but certainly the brother is trying to get Woojin now and wants to control him. That's why he tries to get rid of Hwon.
6- We get to know that after the events with the beggar, Hwon did survived his injury but got lifelong consequences. Hwon wakes up from his injury to find out that no one ever looked for him and Woojin had moved on by then and disappeared. He gets his revenge on the beggar by beating him up -- what lends him to juvenile detention. He doesn't kill the beggar but he dies in a motorbike accident some time later. Hwon grows up resenting Woojin, changes his name and appearance and decides to track Woojin for revenge.
7- Hwon tracks down Woojin with intention to get some kind of revenge. He keeps giving encrypted hints about the past and jogging Woojin's memories but never reveal who he is. He lets Woojin think he might be the homeless kid who killed his childhood friend. Hwon revenge start falling apart as he is still very much in love with Woojin as ever and he gets in the same cycle of chasing, getting beat up and forgiving Woojin and taking him back after every cheating just to be with him. His resentment is still with him though, as he still wants to hear from Woojin why he just left without saying a word.
8- After his second time when he almost dies again because of Woojin and is again left to die alone, it seems Hwon comes to his senses. He finally recognizes that his obsession with Woojin made him an object of entertainment for the other and it seems he is finally ready to let go of Woojin, especially because he thinks Woojin will never change ( his cheating ways, his lack of commitment, leaving him behind when he most needs him, etc).
9- Woojin finally gets his chance to solve whatever things are unresolved in his head about what happened in the past. He is faced with the person he left behind and he needs to answer that question not only for Hwon's sake but for his own.
Sorry if the explanation was too long, the story is long anyway.
OH YEAH !
Guys are you fucking serious ? "gneugneu poor Sungyeon" he deserves completly this situation !
OK Hosik should have to prevent that he spends the night with his friend... BUT I precise that his "nice" husband take the call of Jiwoon (HOSIK'S FRIEND) in HOSIK'S PHONE and dare to ask at Jiwon (HOSIK'S FRIEND) to not call Hosik at night ... REALLY ? It's NOT his business seriously ! It's HOSIK'S LIFE THAT ! The problem with Sungyeon : he is TOO oppressive with Hosik ! He follows him everywhere, wants that Hosik be with him every time it's EXHAUSTING ! Hosik is NOT Sungyeon's property ! He is a human and needs a private life where Sungyeon is NOT here !
Hosik is right to be angry, his husband passed the limit ! Hosik is not only angry because what Jiwon did say and what's happened this night, he is angry about ALL WHAT'S HAPPENING ! From the beginning, Sungyeon is all the time with him ! c'mon, Hosik is NOT a baby, he can take care of himself ALONE even PREGNANT ! What did you think ? Hosik is an adult and have majority ! He MUST BE independent and basically he doesn't need to anyone to take care of himself !
YES Hosik should says to his husband when he is not home, but he can have friends like EVERYONE ! His husband IS NOT his life but an big part of his part, but not enterely his life. Hosik do whatever HE WANTS of his life, his husband have NOT the right to aswer at his calls and touch at his PRIVATED affairs.
Personnaly I can't stand a person like Sungyeon ! I would become insane without oxygene ! -_- Jiwoon is really extreme but he is not totally wrong ! Sungyeon is too ... Too stifling ! Hosik is in Jiwoon's house because HE WANTED be here ! Jiwoon is right ! Hosik needs to be angry at Sungyon to make him understand that he is too stifling !! The communication is very important between lovers, the problem is that Hosik is too nice and doesn't know say STOP and NO. This is the biggest problems of their couple and Sungyeon needs to be stopped. The mariage is one of thing that made me angy Sungyeon CAN'T understand how is difficult to be pregnant in surprise and being a pregnant man ! He imposes directly this mariage to Hosik for me, it was too fast and Hosik was clearly manipulated by Sungyon !