The averages show that the longer couples co-habitate before marriage the shorter their marriage will be. Statistics also reveal that the more sexual partners a person has before marriage, the less fulfilling his or her marital intimacy will be

The averages show that the longer couples co-habitate before marriage, the shorter their marriage will be. Statistics also reveal that the more sexual partners a person has before marriage, the less fulfilling his or her marital intimacy will be.

Many defend the position that it is sensible, logical and even quite prudent for couples to live together before getting married and to “try it out” in order to ensure compatibility. Their metaphors are many: “You wouldn’t buy a car before you had taken it for a test drive.” Or, “try the shoe on first to be sure it fits.” Or, “don’t legalize a partnership until you’re sure you can work together.”

That logic is certainly taking hold. As the Deseret News National Edition recently reported, “Courtship once led to marriage, sex and having children, but today as many as 90 percent of couples reportedly have premarital sex.” finds that “between 30 and 40 percent of dating and married couples report having had sex within one month of the start of their relationship, and the numbers are even higher for currently co-habitating couples.”

We even hear some critical condescension from those who advocate co-habitation. As a young acquaintance recently said to me, “Like, wow, don’t take a chance, bro. That is a high-risk marriage if you just impulsively tie the knot without shacking up for a while first. Be logical about it, man!”

Logical? Prudent? Intuitive? Well, it might sound that way to some people, but here’s the problem: The statistics say exactly the opposite. The data show that the more sex you have had before marriage, the less fulfilling sex will be within marriage. And the longer the time you have lived together unmarried, the shorter the time you will live together after you do marry.

And perhaps even more importantly, the number of unmarried, co-habitating couples that have children is growing as is the number of co-habitating couples that break off their relationship without ever making it to marriage.

Apparently, “trying it out first” is not nearly as smart as it might seem.

Here are three conclusive quotes, taken from a scholarly study by a friend of ours, Dr. Jason Carroll, a university professor who has spent much of his professional life researching relationships:

“The longer a dating couple waits to have sex, the better their relationship is after marriage. In fact, couples who wait until marriage to have sex report higher relationship satisfaction (20 percent higher), better communication patterns (12 percent better), less consideration of divorce (22 percent lower), and better sexual quality (15 percent better) than those who started having sex early in their dating."

“Early sex creates a sort of counterfeit intimacy that makes two people think they are closer to each other than they really are. This can cause people to 'fall in love' with, and possibly even marry, someone who is not a good choice for them in the long run. … You have a better chance of making good decisions in dating when you have not become sexually involved with your dating partner."

“Sexual restraint benefits couples because it requires partners to prioritize communication and commitment as the foundation of their attraction to each other. This gives a different type of foundation from couples who build their relationship on physical attraction and sexual gratification.”

Carroll’s statistics and conclusions are backed up by a recent report from the National Marriage Project at the University of Virginia, “Before ‘I Do.’" The study, as reported by the Deseret News National Edition, concludes:

1. “The more serious premarital relationships you had before, the less likely you are to be happily married later.”

2. “Individuals who had more sexual partners or more experience co-habitating are not as likely to have high-quality marriages compared with those who had less.”

3. “Couples who 'slide' rather than 'decide' their way through life-changing transitions like having sex, living together and becoming pregnant are less likely to report high-quality marriages.”

Counterintuitive? Perhaps. But the truth of it is that real commitment matters more and produces better results than “trying it out.”

Richard and Linda Eyre are N.Y. Times No. 1 best-selling authors who lecture throughout the world on family-related topics. Their newest book, "The Turning: Why the State of the Family Matters and What the World can Do About it," was just published.