In Act 4 of Shakespeare's Othello, Emilia declares that she would not cheat on her husband for a trinket, but she would for the whole world:
It is a great price
For a small vice.
Yet, Desdemona declares that she would not cheat on her husband even for the whole world. Earlier in the play, Desdemona declared that even if Othello treated her badly, she would still love him:
Unkindness may do much.
And his unkindness may defeat my life
But never taint my love.
And, she declared that
I cannot say "whore,"
It doth abhor me now I speak the word.
To do the act that might the addition earn
Not the world's mass of vanity could make me.
Desdemona's love for Othello is pure, constant, and unconditional. She would never cheat on Othello. Unlike Emilia, Desdemona's love is absolute; no price or prize could tempt her to commit adultery; no unkind act on Othello's part could drive her to another man. Under no circumstances would Desdemona cheat on Othello.