Spoiler
So after jiwook gets gang rape for second time (I’m not going to go into detail cuz it was… disturbing), he is so badly injured, he has fractured ribs, a ruptured hole, and he is on the verge of dying in the hospital. The memories of what he did to juyeon come flooding back (he also hired people to gang rape juyeon and sent pictures of him getting raped to his mom), jiwook is anticipating and unsettled while jiwook is in the hospital, but he also does not regret what he does. Jiwook wakes up and reconciles with juyeon about the things he did to him in the past. (Also for context the reason jiwook did these things was because juyeon had a crush on him, the feeling was mutual but jiwook suffered from internalized homophobia.) they decide to stay together and jiwook is living in his house. Sex, sex, sex, and more sex. Jiwook never got the chance to graduate after taking so many leaves of absence (due to being kidnapped and gang raped many times), so he graduates 1-2 years later. They’re still living together fyi. Jiwook gets his diploma, ( I will go into depth for this scene because it is one of the only ‘sweet’ moments between them.) he sees a vendor selling flowers and tells juyeon how it reminds him of juyeon. Juyeon buys the flowers and jiwook says to keep it for himself despite it being his graduation. Then they go outside and jiwook is taking a walk around the campus under the trees while juyeon is grabbing his graduation cap and outfit. This is when jiwook starts having memories of the men who gang raped him. ( by the way, the perpetrators receive no explicit karma and kind of just disappear from the story.) juyeon comes out and notices jiwook panicking, he tells him to take deep breaths and comforts him. Jiwook is calm now and takes the graduation outfit from juyeon and puts it on him. Juyeon is a bit puzzled and jiwook says, “I just wanted to see this.” It was kind of a warm moment. After that sex, sex, sex, and sex. Then they’re back at their home and jiwook starts frequently dreaming about the men who gang rape him. He wants to tell jiwook but is discouraged and afraid. Eventually he tells him and asks if they can sleep together. By the way, juyeon had been celibate for awhile since jiwook was gang raped. So when they had sex it wasn’t with penetration I believe. They’re sleeping together and finally sharing some warm moments. Then after that they’re sleep together again but this time they have penetrative sex because jiwook proposed it, juyeon is flustered and this is the first time we seen him react/blush. Since jiwook was still having nightmares he went to the psychiatrist and got daily medication. Then one day juyeon goes to visit his mother, he doesn’t want to bring jiwook because of past memories. Jiwook is left alone and this time the hallucinations are really bad, they’re telling him to kill himself and he is reminiscing about when he was gang raped. He then grabs a shirt and ties it to a door knob and tried to kill himself. Juyeon saves him on time and scolds him. Jiwook realizes that he likes it when juyeon is angry at him and starts to self harm and do bad things. He eventually stops though because he is afraid of juyeon leaving him. Fast forward to the last two side stories, sex sex and more sex. The revised version was juyeon had gotten jiwook a sex machine as a gift and they fucked for two chapters. The original version was that juyeon had gotten jiwook a dog, jiwook was feeling lonely when juyeon wasn’t around and put honey and peanut butter on his dih for the dog to lick… juyeon noticed this on the cameras he set up in the house (presumably so jiwook wouldn’t try to khs again.) juyeon comes home and puts honey and peanut butter in his ass and makes the dog lick it and fuck him… and it literally ends there
Actually, you completely mixed up the names. Like, Juyeon is the one graduating, Jiwook isn't just graduating late, he's not graduating at all. Also, you got the chapter order wrong, but that's because the site where you read the novel messed up the order (I know cause I read it there too). The chapter where Juyeon graduates is the final one, set 5 years later.

Well I ended up reading the novel and the ending was disappointing and lack luster