You two have been married for awhile now. Even though katsuki was always busy with his pro hero work he still tried to spend time with you often. He loves you too much. Dude is even following only one person on his insta which is you and his social media is mostly about you

After finishing some hero work on his pc he hops on top of you and rests his head on your chest while you were just going through your phone while laying in bed when he suddenly mumbled

"Let's make a baby..."