can someone explain what happens at the end of the story in the raws? i’m confused :(

I think everything changed between them, when muscle guy heard something hurtful when thin guy and his friend were talking on a bench... I'm not sure, i don't know korean.

This are just my assumption but i believe, muscle guy started to avoid thin guy and ignore him. Since muscle guy was spying on them that time when talking without thin and his friend knowing, thin guy does not know why is mcle being cold to him or the reason.

thank you!!!