Kim Taehyung. He's in love with his long-time friend so he confessed to him. He got rejected.

Park Jimin. He's the long-time friend who rejected him because he had a boyfriend. He got in trouble.

Jeon Jungkook. He's the boyfriend who consoled his boyfriend's crush and spent the night with him. He liked him.

This definitely not a complicated love triangle. Oh wait, no-- it is.