Various alternative lifestyles are mentioned in the text, including living together, staying single, and communal living. Living together refers to two people living together without marriage. Staying single means a person decides to live alone, often because they have not met the right person or do not want the commitment of a relationship. Communal living involves a group of people living together based on shared ideals and interests, where members share possessions and skills to be independent from mainstream society. The text also discusses different types of marriages such as monogamy, polygamy, and serial monogamy.