Final answer:
Sexual practices within marriages can vary across cultures and time periods. In the Nyinba society, husbands and wives generally do not engage in extramarital sex. However, in Zande culture, men with multiple wives might lead to infrequent sexual encounters and potential alternative forms of sexual satisfaction among women.
Step-by-step explanation:
Sexual practices within marriages can vary across different cultures and time periods. For example, in the Nyinba society, husbands and wives generally do not engage in extramarital sex. However, it's important to note that sexual practices can differ greatly among different groups and societies. For instance, in Zande culture, men were allowed to have multiple wives and would take turns sleeping with each of them, leading to some wives experiencing infrequent sexual encounters and potentially seeking alternative forms of sexual satisfaction with other women. It is essential to consider the specific cultural and historical context when discussing sexual practices within marriages.