I don’t understand why the author had to include SA just for the sake of plot-driven character development. You can build character development through more realistic conflicts. If the goal was to make that hyung extremely possessive, then when Dae and the hyung met again after that night of misunderstanding instead of SA, the hyung could have distanced himself and tried to properly find out the truth about the red-haired on his own. And now, even after finding out that the private investigator he hired gave him false information, that hyung still continues to use their services.
On top of that,
If this happened in real life, there’s no guarantee that the hyung would truly change—especially since the root of the problem comes from himself, not from someone else.
On top of that,
Spoiler!
I don’t like how the SA is only addressed in two chapters. After that, they suddenly become all lovey-dovey why