Oh, all the strong dark women who are unmarriageable. Cora in The Last Mohican (and isn't it fascinating that they flipped the roles in the movie!) Marian in The Woman In White. The Countess (is it?) in The Age of Innocence.

Assertive and passionate:: destined to be the only person standing on the sidelines at Happy Ending time. By contrast, even a Gilbert and Sullivan contralto usually gets paired with *somebody*.