"Sorry, I gotta go to pick up Taesa." "Sorry, but Taesa really needs me right now." "I'm so sorry, but something happened to Taesa and I need to go." Sorry can only mean so many things- yet the more you said it the more tired I was of it. Jisung sacrified so much for someone who didn't love him back. In your story, he was the second love interest- he was the side character that the audience always loved more than the supposed protagonist's soulmate. But if he was the side character, then what was I? Simple. I was only a mere extra.