*killua's heart, already submerged, sinks deep into the pit of tar at his core.*

b-because...

*he'd gone to her because he's too beautiful, too brilliant and whole to be with someone as broken as him. he'd gone to her because he wasn't enough. these thoughts bubble up in his heart's stead, choking him until a desperate protest breaks through.*

n-no! i didn't -- i didn't know you two had been together until he'd already broken it off...

*...and then immediately got with someone else. killua's eyes are dull, globs of slime building at their corners and threatening to leak over.*