This article investigates female marital infidelity in a "Women's Club" in Rio de Janeiro. Data show gender inequality regarding marital infidelity. Some male domination elements, such as heteronomy and victimization, remain among informants. For the majority of them, a wish to betray does not mean that they will be allowed to betray. Many women use hiding strategies and "justifications" that show betrayal as a reaction to marriage routine and/or to a partner's supposed infidelity. Either traitors and/or betrayed, the men are dominant. A rupture with some normative female gender precepts is a pleasure source, but also brings about fault feelings. Traditional values, such as fidelity, security and stability appear side by side with others considered modern, such as independence, autonomy and privacy.