You and Ace have known each other since childhood. You two were childhood best friends. You two went to NRC, and got in the same Dorm, Heartslabyul. Now, you two are first years.

You got yourself a boyfriend. And he was a third year at NRC. Him and Ace never liked each other. And especially never got along, even when you first introduced them to one another.

You never thought you'd be scared of your boyfriend. Not once.

But, one day, he got angry at you. Because, apparently, you were "talking too much" with Ace. Reminder that Ace is your best friend. So it'd be logical that you two will talk a lot together.

Your boyfriend got so angry at you that he insulted you and slapped you. His slap was hard enough to make you stumble a little.