This is just my thought but I think it's pretty close to accurate.
Uke has Stockholm syndrome + survivor guilt+ Post traumatic stress disorder. He's been raped and repeatedly told that it was his fault but he tried to held out. Then he met the pure seme, the cute beef boy he met before, and was told that his innocent boy became corrupted after watching him get raped, so he start to believe everything was his fault. And then the all shit come tumbling out that makes uke even more sure that everything was his fault. After that uke think he hurt beef boy and dosent deserve him, so he break up with beef boy. Then he tried to go back to his life but Yule show up again. I think uke was tired of running away and believe that he can never escape Yule, so he go back to him, not because he loves him but because he's tired of running away and think he deserve Yule because he's hurt beef boy. In short, it along this line " you hurt me, I hurt beef boy. We're both scum so let's be unhappy together"
The author gave alternative endings for all the ships so I can't really tell
The ones where Kyungsoo ends up with either Yule's bro or Dong Hyuk are the alternative, "what if", endings but the one where he comes back to Yule IS the "epilogue to the main story" as it is stated at the beginning of the last chapter. So in theory, he ends up with Yule, what we'll never know is how that'll result :/
I wouldn't call Dong Hyuk cute puppy/beef dog tho. He acted like a gross horny loser who only wanted to bang Kyungsoo and was so worried about his own dick that failed to get that he needed actual help, not to be harshly fucked 24/7 (he also did raped him when he saw that Kyungsoo fainted and he decided to go for another round the first time they were together). He acted surprised when Kyungsoo said he'd been living with Yule as if he didn't witness he was raped and obviously pretty much forced to be with him. He also decided to sleep around instead of doing something after that. The worst part is that he was supposed to be the ~pure~ character but he helped Kyungsoo's wrong idea of everything that happened to him being his fault for making them lose control. He was a horrible character too...
Ok so all I'm getting is that this book will make me get the feels in the bad way
So does the uke and the twisted seme end up together? Or does the uke and the cute puppy dog seme at the beginning end up together? Cause I can't handle the uke going back to the messed up seme I'm already reading killing stalking I can't handle another messed up relationship.....