[AlphaGam1019]

Here's a good article on cohabitation.

The survey, released by the Centers for Disease Control and Prevention, found that 70 percent of those who lived together for at least five years did eventually walk down the aisle.

But these marriages are also more likely to break up. After 10 years, 40 percent of couples that had lived together before marriage had broken up. That compares with 31 percent of those who did not live together first.

Part of the problem may be attitudes toward cohabitation are different than attitudes about marriage, said Wade Horn, a marriage expert who directs children and family programs at the Department of Health and Human Services.

When living together, he said, the attitude is "I vow to stay together with you as long as you make me happy." In a marriage, people focus on making their partners happy.

"If you're used to viewing being together as a test of the other person's ability to take care of your needs, once you get married it's hard to just switch that," Horn said.