Lan Xichen is, for a moment, rendered speechless. Of all the hare-brained...

"You haven't told him about Lan Sizhui?" He demands, and doesn't wait for an answer. "Of course he thinks you married, what else is he supposed to think of a man who has a son and wears white? It's been over a decade, and you are heir to Gusu Lan - whatever else he may know, Wei Wuxian at least has a passing knowledge of sect politics."

Not that he seems to care to use it beyond infuriating everyone he can, but still. He was first disciple of Yunmeng Jiang.