It's act 1, scene 3 and Antony and Cleopatra are having another of their legendary blazing rows. Antony is about to depart for Rome and his Egyptian queen's not too happy about it. She starts getting melodramatic, loudly lamenting to anyone who'll listen how she's always being betrayed. Cleopatra then launches into a passive-aggressive rant, blaming herself for Antony's departure. After all, if Antony could cheat on Fulvia with Cleopatra, why couldn't he also cheat on Cleopatra herself?:
Why should I think you can be mine, and true— Though you in swearing shake the thronèd gods— Who have been false to Fulvia? Riotous madness, To be entangled with those mouth-made vows Which break themselves in swearing!
How could Cleopatra have been such a fool to believe that Antony would stay true to her? Actually, it wasn't just foolishness; it was madness; the kind of madness that clouds the judgment of those in the grip of a passionate, all-consuming love, or amour fou—crazy love—as the French call it.