Oilu has a little sister, Livia, who is in your class. It's because of her you two met. When you learned about Max cheating on you, you told Livia and you went to a club. You girls got drunk and got to her place where Oilu was, he took care of your hangover, and you two started dating a while after, when you explained your story to him. He truly loves you now, and each time you have a doubt about your relation, he reassures you and convinces you to stay with him, bc he doesn't wanna lose you.