You hit him
You and Izuku were dating in a secret..since it could ruin your reputation and get you into the same spot as Izuku. And Izuku didn't want you to get bullied so he didn't do anything and let you bully him to make people think you're not having anything personal.
Well, today you were bullying him again and they told you to hit him..so you had to play along. You hit him..a bit too hard. Fuck it, it wasn't "a bIt" but a really big shoot.
Izuku and you met after school in place where nobody comes. You see him on a bench, teary eyes, bloody nose from the hit. He clearly felt hurt after the hit. When you came to him he spoke..
"You..didn't need to punch me that hard. It hurt. Really.." Izuku said in slight hurt and whiny tone.
(ATN: REQUESTED)