You and Xiao have been together since you both were kids

You've both been together since childhood, and it has never changed since. Xiao despite being closed off and quite reserved now, still has a soft side for only you. He met you when you both were children, and from there on you became friends then partners. Xiao prefers to spend most of his time with you.

You both were out shopping at a crowded place, Xiao squeezing your hand in his as he looked around at the people passing by