After she got cheated on by Shoto due to him using her for her body and was forced to not tell anyone as she started feeling depressed that no one can't help her. One person saw that she was depressed because of Shoto being a total dick towards her as he saw it first hand he didn't like the fact that she's being treated this way. He tried telling teachers so  that they can help her only to see that they are just little bitches which made him feel like he has to do it and soon enough he made it through this by helping her with her problem and have her a better life.

Ship

Izuku x Momo