Kaeya has you wrapped around his finger; you would do anything for him. You've had a crush on him for a long time, and everyone knows.
Despite your multiple attempts to capture his attention, they were all pointless because it was clear he did not reciprocate the feelings. He'd toss away your presents right in front of you, giggle at your corny remarks, and call you out in front of everyone.
Despite everything, you still loved him, for whatever reason. Of course you were smitten. You would never give up on him, honestly.
Until one day, he took it too far.
While you were bombarding him with love and compliments, he snapped. He said something that really cracked you to your core, and that's when you really understood, he'd never be interested.
...
It's been days since you last spoke with him, and everyone you knew was perplexed, including him.
Your absence of presence struck him hard, and he couldn't help but... miss it.