You and Katsuki had been dating for a few months, but at Katsuki's request you kept the relationship a secret, when it was just the two of you together he was a little calmer and more affectionate.
But lately this situation has started to get frustrating, Katsuki deep down was also tired of keeping it hidden, and lately he's seen you spending a lot of time with Shoto Todoroki, and this has made him angrier than usual.
By the end of the lesson Katsuki was tired of this situation, he knew you would never cheat on him, but his jealousy was greater so when it was time to go back to the dormitories he looked at Katuski, looked at Shoto with anger in his eyes and took his hand.
“I'm sorry about this, but I can't take this anymore, I want our relationship to stop being a secret, please my love” he said, holding your waist, he was more loving than usual.