Relationships: Age 17–45

Love, intimacy, and adult relationships go hand‐in‐hand. Robert Sternberg proposed that love consists of three components: passion, decision/commitment, and intimacy. Passion concerns the intense feelings of physiological arousal and excitement (including sexual arousal) present in a relationship, while decision/commitment concerns the decision to love the partner and maintain the relationship. Intimacy relates to the sense of warmth and closeness in a loving relationship, including the desire to help the partner, self‐disclose, and keep him or her in one's life. People express intimacy in the following three ways:

  • Physical intimacy, or mutual affection and sexual activity.
  • Psychological intimacy, or the sharing of feelings and thoughts.
  • Social intimacy, or having the same friends and enjoying the same types of recreation.

The many varieties of love described by Sternberg consist of varying degrees of passion, commitment, and intimacy. For example, infatuation, or puppy love so characteristic of adolescence, involves passion, but not intimacy or commitment.

In addition to love and intimacy, a deeper level of sexuality is realized during young adulthood within the context of one or more long‐ or short‐term relationships. While the maturity level of the participants affects adolescent sexuality, adult sexuality is fully expressive. Following are discussions of some of the most common types of adult relationships.


Today, many people are choosing singlehood, or remaining single, over marriage or other long‐term committed relationships. Many singles clearly lead satisfying and rewarding lives, whatever their reasons for not marrying. Many claim that singlehood gives them freedom from interpersonal obligations, as well as personal control over their living space. As of the late 1990s, 26 percent of men and 19 percent of women in the United States were single adults.

Most singles date; many are sexually active. Typical sexual activities for singles are the same as those for other adults. Some singles are celibate, abstaining from sexual relationships.

Cohabitation and marriage

The two most common long‐term relationships of adulthood are cohabitation and marriage. Cohabitors are unmarried people who live and have sex together. Of the more than 3 million Americans who cohabitate, most are between the ages of 25 and 45. Many individuals claim they cohabitate as a test for marital compatibility, but no solid evidence supports the idea that cohabitation increases later marital satisfaction. In contrast, some research suggests a relationship between premarital cohabitation and increased divorce rates. Other individuals claim that they cohabitate as an alternative to marriage, not as a trial marriage.

The long‐term relationship most preferred by Americans is marriage. Over 90 percent of Americans will marry at least once, with the average age for first‐time marriage being 24 for females and 26 for males.

Marriage can be advantageous. Married people tend to be healthier and happier than their never‐married, divorced, and widowed counterparts. On average, married males also live longer than single males. Marriages seem to be happiest in the early years, although marital satisfaction increases again in the later years once parental responsibilities have ended and finances have stabilized.

Marriage can also be disadvantageous. Numerous problems and conflicts arise in long‐term relationships. Unrealistic expectations about marriage, as well as differences over sex, finances, household responsibilities, and parenting are only a few potential problem areas. Severe problems may lead one or both spouses to engage in extramarital affairs.

Extramarital relationships

Nonconsensual extramarital sexual activity (not agreed upon in advance by both partners) is a violation of commitment and trust between spouses. People express various reasons for engaging in extramarital activities; in any case, such affairs can irreparably damage a marriage. Marriages in which one or both partners are unfaithful typically end in divorce. Some couples may choose to stay together for monetary reasons or until the children are grown.


When significant problems in a marital relationship arise, some couples decide to divorce, or to legally terminate their marriage. About 50 percent of all marriages in the United States end in divorce, with the average duration of these marriages being about 7 years.

Both the process and aftermath of divorce are very stressful on both partners. Divorce can lead to increased risk of experiencing financial hardship, developing medical conditions (ulcers, for example) and mental problems (such as anxiety or depression), having a serious accident, attempting suicide, or dying prematurely. The couple's children and the extended families also suffer during a divorce, especially when disagreements occur over custody of the children. Most divorcees and their children and families eventually cope, and about 75 percent of divorcees remarry.


Friends play an important role in the lives of young adults. Most human relationships, including casual acquaintances, are nonloving in that they do not involve true passion, commitment, or intimacy. According to Sternberg, friendships are loving relationships characterized by intimacy, but not by passion or commitment. In other words, closeness and warmth are present without feelings of passionate arousal and permanence. Friends normally come from similar backgrounds, share the same interests, and enjoy each other's company.

While many young adults experience the time constraints of going to school, working, and starting a family, they usually manage to maintain at least some friendships, though perhaps with difficulty. That is, as life responsibilities increase, time for socializing with others may diminish.

Adult friendships tend to be same‐sex, nonromantic relationships. Adults often characterize their friendships as involving respect, trust, understanding, and acceptance—typically the same features of romantic relationships, although without the passion and intense commitment. Friendships also differ according to gender. Females tend to be more relational in their interactions, confiding their problems and feelings with other females. Males, on the other hand, often hesitate to share their problems and feelings, instead, seeking out common‐interest activities with other males.

Friends provide a healthy alternative to family members and acquaintances. They can offer emotional and social support, a different perspective, and a change of pace from daily routines.