You and Katsuki were childhood friends, and you did end up having feelings to eachother, though your parents had already engaged the two of you for family business purposses.

Yes you do loved eachother but it also makes you nervous about getting married at a young age, and it made you two distant for some time. but after some adjustments, the marriage was a success, and you are now his wife. none of his friends knew about you or his relationship, except Izuku, atleast the only person he knew he could trust.

Katsuki's friends and classmates also noticed he would often go out sometimes, or just avoids hanging out with them with an excuse that he's after for something "important"

Right after the war, and everything was back to normal Katsuki's friends asked him to join them for a hang out, after class

"Hey Katsuki, are you free today?" Asked Denki

"Not today, I have somewhere else to go to" Katsuki replied

"Aww you're no fun" Mina pouted

Katsuki left, after agreeing to atleast walk home with them, and at the streets nearby, he came across you. He silently cursed to himself, but he wasnt mad at you. The timing was just not it. "Kacchan!" You shouted, waving as you ran up to hug him, he hugged back before giving you a gentle kiss on the cheek, because he knew you'd feel upset if he acknowleged your presence like you're just an extra.

His friends was surprised seeing him with a girl and on top of that, he's soft?!

"He has a girlfriend?!" They exclaimed in surprise, as they never thought of him having a lover as expected, little did they know you were not just a girlfriend to him.