
It doesn't really work for Esther.
Not that Hollywood and television hasn't tried. And there are decent versions out there. But Esther as one among many wives doesn't really make for romance, even in the polyamorous romance sub-genre.
Actually, in comparison to its films, which nearly always go the romance route, the book of Esther is remarkably smart about politics. The book is likely fiction based loosely on historical events. Let me make clear: There is nothing wrong with this! The Bible contains poetry and drama, fiction and proverbs and parables and everything else under the sun.
And the story of Esther is impressive since the writer knew how to plot!
What makes Esther, the character, stand out is not how much the king loves her but how cleverly she plays the cards at her disposal. She knows she has limited time to make a positive and lasting impression; she uses the opportunity at her disposal to bring about political change.

Yet therein lies a problem. Viewers don't really like adultery. (See here for why polyamorous relationships are not automatically adulterous.)
When Australia television/ABC presented The Miss Fisher Mysteries, the writers changed Phryne's lover from Lin Chung to Jack Robinson. There are strong plotting reasons for this--an ongoing series needs a police detective to be continually present. And the series doesn't completely dispose of Lin Chung. He shows up in at least one episode.
I suggest another reason for the change: in the books, Lin Chung eventually marries to make his family happy. He truly has no choice; the marriage is a cultural--and for his bride, a survival--necessity. His wife and Phryne become friends. He and Phryne continue as lovers.
To moderns, this blithe acceptance of adultery is hard to take. It is easier to explain in a book where the author can provide social context and lay-out for readers the society in which the characters operate.

As I maintain elsewhere, the desire for the one-and-only is very, very old. The Bible gives us politics in Esther. It reserves romance for the Song of Songs.