Oh no. It seemed like Sangwoo was sexually abused by his mother, after the dad died and t...

Oh no. It seemed like Sangwoo was sexually abused by his mother, after the dad died and this is why Sangwoo has such conflict and trauma relating to be seeing as Bum's (who he overlaps with his mother) and sexual partner. Whenever Bum is more sexually dominant, this reminds him of his mother's abuse. Ditto the effect of shock that Sangwoo has, whenever Bum calls him with the honorific that his mother used (Sangwoo ya, instead of his usual ssi) which is something Bum does especially when he is being sexually dominant. This also maybe explains Sangwoo's murders that had relatively nothing to do with Bum, which amounts to the CEO's daughter at the start and the women at the ski resort who Sangwoo was shown in the latter to be into some sort of visual hallucination of his mother, and he spoke of the first woman in reference of trying to escape, to cease his mother's torment. It's also worth noting that until recently Sangwoo was saying that he was having terrifying nightmares and audio hallucinations of his mother, and this lessened when Bum started to stay with him. So Bum provides both a comfort, but he also can't block out his family abuse completely. Still don't think he would harm Bum. he needs Bum to carry on with life and who knows him more than anyone else, more than Bum needs him. Bum's became obsessed with more people than just Sangwoo before, whereas Sangwoo has had the biggest connection in his life (apart from his parents) only with Bum.