Nearly half of people in their 20s and 30s live together before marriage. But studies show cohabiting couples typically experience more stress and less success than those who marry.

"There is so much social pressure today to cohabit," says Dr. Barbara Markey, associate director of Creighton University's Research Center for Marriage and Family. "A person's social desirability is based on who you are living with - if you aren't living with someone, there is clearly something wrong with you. We need to give people who are thinking about cohabiting the heads-up. It isn't all it is made out to be."

Why do people live together? Some consider it a test of compatibility. Others say it's financially beneficial. Still others see living together as a good alternative to marriage.

Experts say none of the above is true, because cohabiting relationships differ significantly from marriages. "Instead of promoting harmony, living together often promotes discord or individualism," says Markey. "Instead of thinking in terms of 'we,' most cohabiters think along the lines of 'yours' and 'mine.'"

Markey says the behaviors learned when cohabiting can get in the way of a successful marriage. "In many instances there is competition about money and independence, where marriage is characterized by interdependence," she says.

This may be part of the reason that couples living together have an increased chance of divorce if they do marry-although more than half of those living together will not get married. Cohabiting couples also have a greater incidence of abuse and unfaithfulness, and they are many times less committed to each other and to their exclusive relationship.

More than 40 percent of cohabitations now involve children. And research shows children with divorced or cohabiting parents are more likely to live in poverty, have trouble at school, have physical and emotional problems, and use drugs and alcohol.

Adults who cohabit because they fear the commitment of marriage or the pain of divorce can also find themselves suffering.

"People need to understand that they are not putting themselves in a position to experience less pain," says Markey. "Cohabiting often leads to heartache and pain."

She says young people can best prepare for a great marriage by learning to live independently. "So many young people are leaving home and moving in with a significant other, thinking they are establishing their independence," says Markey. Instead, she says, they're actually continuing their dependence.

"Young people need to learn what it is like to live on their own - being responsible for the rent, car payment, food, light bill," Markey says. "I encourage people to take the time to learn their own individual style before trying to blend with someone else."

The best way to prepare for marriage at any age is through premarital education. A good marriage preparation program uses an inventory to help you recognize your strengths and weaknesses as a couple. You should also take a course to learn healthy problem-solving and communication skills that will dramatically increase your chances for success.

To find classes in your area, visit our classes page and choose a county near you. If you don't see a nearby county, check our list of individuals and organizations certified in PREPARE, a marriage preparation course we highly recommend.

To learn more about the drawbacks of living together, check out "All About Cohabiting Before Marriage." You'll find enough detailed information and data to convince anyone you love that living together can ultimately drive you apart.