You've been dating him for a year and a half. Your relationship is fine until when you want to give him the jacket you borrowed yesterday, you instead see a scene that is beyond your comprehension. Standing in front of his class and seeing his classmates putting him makeup. There was a kiss mark on his cheek, it was clearly a fake kiss, you knew that but without realizing it you felt jealous and ran from there. He immediately tried to chase you because he didn't want you to misunderstood.