Beomgyu(you) and Yeonjun have both been in a toxic relationships. They were best friends till Yeonjun confessed his love you. He promised he would be different then your past lovers. Yeonjun said he would change since he was the toxic one in past relationships. "Yah get over here." He yelled. He ended up returning to his toxic habits and would yell, abuse, and hit you. Deja vu, isnt it?