Scripture is clear. "Flee fornication," Paul warns (I Cor. 7:18). What is cohabitation but fornication raised to the 100th power?

The outcome of sin can never be good.

As my wife and I reported in our book, Living Together: Myths, Risks & Answers, many couples live together to test the relationship for marriage. Big mistake.

While two-thirds of couples who marry are living together, 1.4 million, what happened to the other 6 million? Most broke up, sadly discovering that cohabitation is a trial divorce, not a trial marriage. Many experience "premarital divorce" that is so painful, millions never do marry.

The number of never-married Americans has tripled from 21 million in 1970 to 63 million in 2008, six times population growth. Result: the marriage rate fell by 51 percent.

However, couples who marry after living together, have better marriages because they know what to expect, right? No. That's a myth. A Penn State study reports that such couples are 61 percent more likely to divorce than those who remained apart, the Christian norm for 20 centuries. Another Penn State study found that even living together for 30 days diminshed the quality of the relationship.

Only about a tenth of cohabiting couples build a lifelong marriage.

My question for pastors is simple: Why are you silent on this issue? Why not use these numbers to make a case for remaining apart?

While few cohabiting couples are in church, their parents are there, and don't know what to say to adult children who want to cohabit. Two-thirds of teens think cohabitation is a good idea. They must hear evidence of its harm.

When cohabiting couples ask pastors to marry them, why not insist that they move apart until the wedding? That's the stand of Pastor Jeff Meyers of Christ Lutheran Church in Overland Park, KS. When couples claim they can't afford to move apart, he replies, "Sue, we have widows in this church who would love to have you move in until your wedding."

Four out of five move apart, and not one woman asked for the name of a widow. She would rather move home for several months or in with girl friends.

Fortunately, there is a much better way for couples to test the relationship. As Paul urged, "Test everything. Hold onto the good. Avoid every kind of evil (I Thess 5:21-2). "

Cohabitation IS evil. That's what a 90 percent failure rate is, before or after the wedding.

My wife and I have trained thousands of couples in healthy marriages to be "Mentor Couples" for churches who help couples take a premarital inventory, a detailed questionnaire, which asks them to respond to 150+ statements like these:

1. I am concerned that my partner is more of a spender than I am.

2. When we are having a problem, my partner often refuses to talk about it.

Mentors can then react to exactly what the couple has said about themselves. I might say, "George, if she asks a question and you don't know what to say, don't walk out of the room. Ask her, "Can we talk about this after dinner?" That gives you time to develop an answer.

Any couple married 20 years can offer that sort of wisdom or common sense.

Thus, churches can help couples test their relationship appropriately.

Furthermore, groups of churches can come together across denominational lines, and require all couples getting married in that city to take an inventory and be mentored. My wife and I have helped 10,000 clergy in 229 cities create a Community Marriage Policy with a conscious goal to cut their divorce rate.

An independent study of the first 114 cities found that divorce rates fell by 17.5% on average. Equally important, cohabitation rates fell by one-third compared to similar cities in that state. Marriage rates are rising.

If clergy cooperate, they can fight cohabitation and create a new marriage culture.

Copyright 2010 Michael J. McManus