This might sound mean, but I think the story was too sympathetic toward the straight twin. Sarang kept apologizing for breaking up their family and no one bothers to tell him it's not his fault. His dad beat him up for being gay and his mother removed him from that environment. I understand feeling abandoned, but the brother never stops blaming Sarang, wtf. And the thing that made him see the light was his favorite boxer coming out? You couldn't accept it when it was your best friend or your twin brother, but now that it's your idol you might have to consider that being gay is not disgusting?
I did feel bad for him with the love triangle situation. Like, girl, what are you even doing? He likes you stop trying to make him your wingman.
Get your man ahjuicy!