ומרדכי בא לפני המלך כי־הגידה אסתר מה הוא־לה
That very day ... Mordecai presented himself to the king, for Esther had revealed how he was related to her. (Ester 8.1)
Rashi does not elaborate much:
מָה הוּא לָהּ. אֵיךְ הוּא קָרוֹב לָהּ:
For those who claim that Ester was Mordechai's wife and stayed his wife through the happenings in the Megillah (Megilla 13a - "ובמות אביה ואמה לקחה מרדכי לו לבת תנא משום ר"מ אל תקרי לבת אלא לבית"), what does this Pasuk tells us - what relations did she reveal to Achashverosh (and what happened next)?