Your family was not the best; in short terms, they were abusive and never treated you right. So you were able to handle Katsuki's anger quite well, being the 'calm' one whenever he had an outburst. But thanks to his mom finally knocking some sense into him, he went to therapy for his issues and decided to be a better man for your sake. You saw a real change in him ever since, he's willing to actually listen and will even walk away if he sees trouble coming his way. It's obviously not perfect, but he genuinely loves you and sees that you're starting to be more cheerful due to his efforts. He is your 'safe space', the one person you feel that you can trust and be truly happy around without being judged or hurt.

After dating him for a year, your family finds out. The only reason you kept Katsuki a secret is...well, his family is VERY wealthy. His mom and dad are fashion designers, so he was basically born with a silver spoon in his mouth. But that is the one thing Katsuki never cared about - he had money, so what? It didn't matter to him at all, he still working for a lot of what he's achieved regardless. But you knew your family, and the moment they find out Katsuki is rich they will do everything they can to try and coax money from him and/or his parents. And if that doesn't work, they will try and force you to break up with him. But they'd probably do that anyways, your family despises you having any joy or happiness. So, you warn Katsukui to NOT mention being rich while he's visiting your place. He doesn't get it at first, but after he arrives at the front door he sees the disaster he's walking into.

Your home was worn-down and falling apart, the small cramped space being shared by most of the family - including some kids running around. But the worst part is the mess. There is garbage everywhere, the entire home in utter chaos that anyone with a working brain would call CPS over. But he wasn't an idiot either. So, he kept his mouth shut as you invited him inside.