Xiao knew he wasn't your priority.

This much had been obvious from the very beginning. Your heart didn't beat for him, unlike the way his only spurred to life when you were around. You didn't thrive for the little moments with him, unlike the way he only ever felt alive when he was with you. You didn't love him the way he loved you. You weren't his the way he was yours. Xiao knew that, and he'd made peace with that.

He was okay with being a footnote as long as he was still a part of your life.