If you are researching this as a real-world relationship dynamic (often referred to as the "Hotwife" or "Cuckold" lifestyle), the "guide" focuses heavily on ethics and communication: Consent is Absolute:

In the context of adult fiction, this theme typically focuses on: The "Double Life":

Beyond the Archetype: Subverting the Narrative of the "Submissive Wife"

Some discussions touch upon the "esposa-puta" concept as a way to explore the sharp divide in traditional perceptions between respectable wives and "prostitutes".