Husbands should be like Kleenex; soft, strong and disposable.
~ Mrs. White in Clue.

A "Black Widow" is a common type of villain in folklore, fiction, and real life. These are women who make a habit of marrying men and then murder them in cold blood, sometimes for money, but a black widow can also be a specific type of serial-killer. They are, of course, a sub-type of Femme Fatale, but are almost always deadly, that is unless they're caught in time.