The female lead is the absolute worst in the manga.
The fact that she cheats on her husband with his piece of shit brother WHILE he's in the hospital makes me hate her so much. She claims she won't be with either of them, but she will probably end up with the piece of shit brother.
I think the true villains are both the Mom and female lead since they knew the truth yet abstained from “hurting” others, which resulted in a failure since the MC was constantly in pain.