Honestly, he has a way more valid reason to hate/ignore her.
However I wouldn’t justify enough for him to actually neglgect to communicate to her. He eventually realizes that she would do anything for him, in the past life. He even describe it. So he wasn’t justified in just staying silent the whole relationship and not explaining anything to her.
But also, she did not understand him. She probably didn’t know how the fuck he got to Korea its just that he is handsome and a S class Esper. She honestly should have communicated it better with words though I found her actions to be sufficient.
Lesson of the day: Communicate it helps.