I don't think she was banished. She was still his wife when she uncovered Haman's plot at the end of the story.
Ummm...no I mean Vashti was banished. The king married Esther and she later uncovered the plot against the Jews.
History shows that Xerxes has a son later, but NOT that Esther was the mother. I was wondering if Esther died & if Vashti returned to her original position as queen. I didn't know what Jewish tradition stated what happened to Esther AFTER she save her people.