Tear Jerker / Dark Heaven

• Conor's bullying throughout grade school. Mind you, thing do get slightly better for him after befriending Simon and Mona, but the pain he suffered is not something any child should go through.
• The flashback chapters ending with Conor and Simon's break-up. Even before that, things were getting shitty for the pair with Conor's hands crippled from his Homophobic Hate Crime incident and Simon being rejected by the Lees after they learn the truth about their relationship via nude pics sent to their phone.
• Kiev being a complete Jerkass to Conor stems from him being treated coldly by Mr. Lee for his father's actions. While the alienation he gets is bad enough, him not being added to the family registration despite Mrs. Lee's insistence further cements his status as the Black Sheep of the household. His resentment is fueled even more by his unrequited feelings for Simon.
• Gale's Dark and Troubled Past shows why he's become such a Psychopathic Manchild. Being the Literal Bastard of Alster Winsor and his mistress, he was forcefully groomed to follow in his father's footsteps as a scholar and even had his hair dyed blonde to invoke the Strong Family Resemblance trope. If you think that's bad enough, it gets even worse: he gets raped by his own father and even his mother encourages it or joins in. This, along with every stressor in his life, deteriorates his psyche to the point of neurosis. The only thing keeping him from becoming a Complete Monster is his twisted sense of morals.
• Conor and Simon's date night to celebrate their nuptials is cut short after the latter confronts Veronica and gets shot by her. The chapter following it is a rather tragic Dream Sequence which has Simon sharing all the things he wanted to do with Conor.
• The entirety of chapter 80. The scene where Mrs. Lee comforts a crying Conor over Simon's Heroic Sacrifice is juxtaposed with a memory of when he was confused about his sexuality following the break-up, tearfully asking if being cured would end his heartbreak. At the end of the chapter, she finally accepts her son's relationship with Simon and mends ties with both of them.