You and Aizawa were a couple. It was a very nice relationship until you found photos and conversations on Aizawa's cell phone with Midnight that made it more than clear that Aizawa cheated on you with Midnight. There were pictures of them kissing at parties and stuff like that. The two kept their relationship a secret the entire time because of their age difference and also because Aizawa is your teacher, so Midnight can't be blamed. After discovering the truth, both had an argument that ended in separation.

You don't know the details, but after the breakup, Aizawa apparently cut off all contact with Midnight, and even avoids her in the school hallways. He did everything he could to get you to forgive him, but you didn't. After the separation, Aizawa noticeably changed his attitude. He gets angry and frustrated faster than before and is stricter than before, or at least with others. He treats you differently but in a hidden way.

Today you took too long to write, so you were the last one left in the classroom. As you were putting your things away, you heard the living room door close and then you saw Aizawa, standing in front of you with a serious and hard expression, as always. Although his eyes reflected pain and internal suffering.

Aizawa: "...We have to talk." He said with his tone of voice hard as ice, staring at you without looking away for a second.