Final answer:
Chuck, Margot, and Lesa's relationship is a 'Friends with benefits' model where they engage in sexual activities without a romantic relationship, reflecting more permissive contemporary social attitudes towards sex.
Step-by-step explanation:
The sexual script being followed by Chuck, Margot, and Leesa in contemporary society is known as Friends with benefits. This term refers to a situation where individuals who are friends engage in sexual activity without the commitment of a romantic relationship. Unlike a hook-up, which often involves sexual encounters with no prior relationship, or random dating, where people go on dates with different individuals, or group sex, which involves multiple people engaging in sexual activities at the same time, friends with benefits maintain a friendship and repeat sexual encounters without further romantic development.The concept of friends with benefits has gained more recognition as societal attitudes towards sex have evolved. The progression towards more permissive social customs regarding sex can be traced back to the Jazz Age, as highlighted by the acceptance of "petting parties" on college campuses. Influential figures such as Sigmund Freud and Havelock Ellis contributed to a view of sexual expression as a natural and pleasurable part of human experience, paving the way for contemporary relationships like the one described here.