At some point, women become sluts. They lose the taste for monogamy. This seems to take place somewhere between 10 and 20 partners. According to this chart, it is somewhere after 15:

In the movie What’s Your Number?, the number is: 20.
Here is Goethe, in Faust Part I (“Night”) from 1808. The number here is, apparently, 12.
Valentine: My Gretchen, see! Young you are still
And shrewd enough by no means quite.
You manage your affairs but ill.
In confidence I tell you, what is more,
Since once for all now you’re a whore,
So be one then outright!
Gretchen: My brother! God! What words to me!
Valentine: In this game let our Lord God be!
Now what is done is done, alas!
And as things can, so will they come to pass.
With one you started secretly,
And more of them there soon will be.
When a dozen men have had you down,
You’re common then to all the town.
When Shame at first is given birth,
She is smuggled in upon this earth,
And then the veil of night is thrown
Around her ears and head;
Yes, one would gladly murder her instead.
But when both proud and great she’s grown,
By daylight then she goes forth openly,
And yet has not become more fair to see.
The loathsomer her face, straightaway
The more she seeks the light of day.