Remaining single instead of marrying or living together, or following divorce, has become an increasingly prominent lifestyle in the United States. In contrast to 1970, four times the percentage of men and women between 30 and 34 years old have never been married—33%

of men and 25% of women (Straus, 2006). Single adults comprise 45% of the population in the United States (DePaulo, 2012). The increased number of single adults is partly due to men and women marrying later ( Jayson, 2012). The median age at first marriage has risen since 1970—from age 23 to 28 for men and from age 21 to 26 for women (Wolfers, 2010). However, the main reason for the increase may be that more people prefer to be single. A recent survey found that 55% of unmarried individuals said they were not looking for a committed relationship (DePaulo, 2012).

Not long ago, women who pursued higher educa­tion were more likely to remain single. However, today they are more likely to marry than are women with lower levels of education, although they marry later than the average woman due to their desire to establish themselves professionally before marriage (Romano, 2009).

Single living encompasses a range of sexual patterns and differing degrees of per­sonal satisfaction. Some people who live alone remain celibate by choice or because of lack of available partners. Others are involved in a long-term, sexually exclusive relation­ship with one partner. Some practice serial monogamy, moving through a succession of sexually exclusive relationships. Some single people develop a primary relationship with one partner and have occasional sex with others. "Friends with benefits" (FWB) are relationships with a blend of friendship and physical intimacy outside a committed romantic relationship. Researchers found that most women and men had more positive than negative emotional reactions to their FWB relationships, although men were even more positive about FWB relationships than women were (Owen & Fincham, 2011). Still other single adults prefer concurrent sexual and emotional involvements with a number of different partners. Regarding one-night stands and single life, a study found differences between men and women. Eighty-one percent of men, compared to 54% of women, said that they enjoyed the experience, and women were much more likely than men to say that they regretted having had the one-night stand (Campbell, 2008).

Most single people are happy with their nonmarried status, whether temporary or permanent (McGinn, 2006). In terms of how happy singles are about their sex lives, research suggests that married people experience higher levels of sexual activity and satisfaction than singles, but many singles claim that their sex lives are more exciting (Laumann et al., 1994; Schachner et al., 2008).