True to form, even after a serious misunderstanding that left their entire relationship at risk, Jaehyuk is still more focused on the validation he feels from Garam’s distress/betrayal when he thought he’d been cheated on than actually comforting and alleviating Garam’s distress.
Jaehyuk is a major player, has been mostly straight, and has made degrading comments to Garam about his sexuality in the past. Under those circumstances it’s entirely reasonable for Garam to assume he’s cheating. And even when his relationship is imploding and his partner is in severe distress, he’s still only thinking about himself.
Even the original fight was about him being offended that Garam was not progressing in the relationship (thus providing higher levels of emotional gratification) fast enough. Any jerk can say “I love you”, but it takes time for someone to be ready to feel and say it.