"There are a couple of big issues in understanding cohabitating couples," Karney says. First, on average, different types of people decide to live together rather than opt for marriage. This self-selection produces outcomes that contribute less to well-being and happiness than people who choose to get married.
People who choose to cohabitate often have weaker relationships, he adds. Also, studies show there is a higher rate of domestic violence in such relationships. "Commitment is the driver here," Karney says. "Because they have a reduced commitment, they don't bother to get that piece of paper [a marriage license]." Economic stresses also lead couples to live together rather than marry. It is no accident, Karney and others say, that the decline of marriage and traditional family structures has occurred during the sustained economic decline of the nation's middle class.
Whatever the outcome of cohabitation may be for the average couple, individual couples who decide to live together need not accept an average outcome. Sociologists ascribe four types of benefits to marriage—intimacy and commitment, complementary household roles, societal support from friends and family, and legally guaranteed benefits such as joint tax returns and health insurance.
There is very little reason unmarried couples can't enjoy the same strength of commitment and household partnership as married couples. Some researchers have found that the relative ease of ending an unmarried relationship tends to weaken its bonds compared with a legally sanctioned marriage. Again, this may be true on average, and not necessarily for any specific relationship.
Robles provides several examples of things that couples can do to maintain or increase their happiness:
• Sharing novel experiences.
• Doing something new together.
• Sharing good news, whether it's life-changing or part of a day's experience.
• Responding positively when your partner shares good news.
Unmarried couples also may need to work harder to develop and maintain mutually supportive household roles. In many marriages, for example, women tend to reinforce healthy eating and good healthcare practices. They also tend to be the dominant developer of social relationships for the couple. Carrying out such roles can be harder when the partners are not married.
The three elements of successful relationships, according to Karney, are: the qualities of the two people involved that make them better or worse at relationships; the qualities of their immediate circumstances; and the qualities of their interactions. Negative factors—career setbacks, financial issues, weight gain, a recession, family and friendship squabbles—can all sidetrack the development and growth of an intimate relationship. "When life is hard, intimacy is hard," he concludes.
"Getting along with another person who is not identical to you, and who inevitably wants different things than you want, is hard work, even in the best of circumstances," Karney says. A key ingredient is to make the effort to understand the other person's point of view and step outside your own, he adds.
To understand what someone else is thinking and what's important to them is not only a key to being a responsive partner, but a sign of great respect for the other person. "Part of doing that is appreciating the invisible forces in the relationship," Karney says. These may include what kind of day they had and what else is going on in their lives. He adds: "Those invisible forces can help us understand our partners better, and we can give clues to our partners as well about how we are feeling."