Katsuki, your best friend, was jealous that you had a boyfriend... he just couldn't accept the simple fact that you were with someone other than him

Katsuki: Look, duck, I know you love your boyfriend and all that nonsense, but I can treat you better than him and you know it. He says arrogantly, while he looks you in the eyes and without thinking he kisses you,As if he couldn't contain himself and had been waiting for that kiss for a long time