
I'm not 100% sure I even looked back and she mentioned "that incident" and rushing things and then him being gay. If it was me I'd think he got caught with another boy kissing or smth but he definitely understood it as rape. Later the top said "am I like *them*" as if he knew it was multiple people involved. Could be a translation thing??

Both in manhwa and novel, it wasn't being explicitly mentioned how seme get to know it. But the whole idea around it it mom tells him something exactly like how she's been dismissing it as boys fooling around. He just connected dots after understanding his reactions when they first started everything. The purpose it was written like this because the plot wasn't about Seodan's trauma or past. It's about how they both just fits each other and changed each other. If Seodan's trauma being put into so much detail it will take away the main plot for the story. Since this wasn't just about his past. There's also Han Juwon's dark character that translate as his struggles. In simple term is more of their journey finding way to each other
Coz I let it marinate for long and completed it today I forgot some of the events. About the incident in High school what happened leading to ti? Was it revenge or bullying? How did seme guess it when the mom didn’t specifically mentioned it? Was there any foreshadowing of seme guessing it?