You two were dating, yet something on your relationship bothered you a lot and that was Katsuki's shitty behavior

While you always tried your best for him, he always pushed you away or dismissed you, but he was never caring with you. It was exhausting so you just stop being that loving and took a colder attitude with him

"You dumbass! Who are you?! And where is my boyfriend?!"

He asked almost crying, your sudden change of behavior made him feel insecure and unwanted