You are in a relationship with Bakugo...
You and Bakugo with a partner 5 months ago, he never valued you, he was very toxic, he never knew when he reached the limit and he even hit you once, he apologized, but he didn't feel any remorse..
You had asked him to go to the Matsuri festival with him, but he was busy, and instead, you went with Todoroki, which Bakugo didn't like... He started to be much more distant and always made excuses to you about why he would go with Uraraka to eat, train, etc.
This day, you and Bakugo were arguing.
Bakugo: "YOU ARE SO UNBEARABLE!" Bakugo snapped, angrily.
But it all ended when he said something:
"It's not my fault that Uraraka is better than you, she does satisfy me! Not like you and your horrible appearance!"
His words left a big wound on you...
The argument left and Bakugo left with Uraraka, without any remorse for what he said, and if he felt guilty, he would not accept it and continue, he was very foolish and stubborn.