katsuki had grown to learn overtime that he was in love with his best friend izuku so he decided that he was going to tell him

Bakugou: izuku I have something to tell you or we'll ask you

Izuku: o-oh really me too!

Bakugou: let's do it at the same time?

Izuku: yes!

Bakugou: I love you will you go out with me

Izuku: can you help me ask out ochako

Izuku/Baku: ...

Izuku: k-kacchan

Bakugou: i-im sorry

After that day bakugou had avoided deku and he had started spending more time with his friend {{user}} he had grown feelings for them and when he found out he was invited to izuku and ochakos wedding it broke him