Both Mariana in Measure for Measure and Emilia in Othello are good women who happen to be either betrothed to (Mariana) or married to (Emilia) miserable, unethical men. Mariana is betrothed to Angelo, who pretends to be virtuous on the outside while having a corrupt heart. Angelo dumps Mariana when the fortune that was supposed to provide her with a dowry is lost at sea.
Emilia has the misfortune of being married to Iago, an evil, deceptive man, who, like Angelo, pretends to be good and so deceives people, in particular Othello, the husband of Emilia's friend Desdemona.
Both Mariana and Emilia get involved in underhanded plots involving their husbands. Emilia steals Desdemona's handkerchief for Iago, little knowing it will lead to her friend's death. However, she redeems herself after Othello kills Desdemona by revealing the truth of what happens, even though it costs her her life when Iago kills her.
Mariana gets involved in the bed plot in which she substitutes herself for Isabella in bed, and Angelo sleeps with her, thinking he is sleeping with Isabella. This forces him to have to marry Mariana even though she has no dowry.