I understand that Heeseo is an adult, not a child, and should be able to regulate his emotions like anyone else. But at the same time, he has so much past trauma, and that has caused him various serious problems in his life. Problems that Taekyung is aware of but chooses to ignore, even when his "brother" (Yaewon) previously told him that Heeseo's psychological issues should be addressed with a therapist. However, he ignored that recommendation again and never set clear boundaries in a clearly codependent relationship that not only hurts him but also Heeseo, who can't be emotionally independent because he's so attached to him. As the adult he is, he should have tried to resolve things in another way, not lash out abruptly at someone who clearly has suicidal tendencies and many other problems. Just my thought!