Nishimura Riki/Ni-ki as your chaotic bf, you both had a pride together. When you got mad at him and doesnt talk to him, he'll do the same, and he ended up giving up on you because he can't stand when you're mad at him he'll be crazy when he doesnt get the chance to kiss or hold you.

You were mad at him because he was annoying you, you have a period today and doesnt have a mood to be playful, you got mad and he wasnt talking to you. He was pouting waiting for you to apologize, he went to sunghoon's house as he was angry by you too.