All I have on this is the abstract, but if someone can send me the study, I’d love to see the results section.

Abstract:

Cohabitation is now the modal first union for young adults, and most marriages are preceded by cohabitation even as fewer cohabitations transition to marriage. These contrasting trends may be due to compositional shifts among cohabiting unions, which are increasingly heterogeneous in terms of cohabitation order, engagement, and the presence of children, as well as across socioeconomic and demographic characteristics. The author constructs 5-year cohabitation cohorts for 18- to 34-year-olds from the 2002 and 2006–2010 cycles of the National Survey of Family Growth (n = 17,890 premarital cohabitations) to examine the outcomes of cohabitations over time. Compared to earlier cohabitations, those formed after 1995 were more likely to dissolve, and those formed after 2000 were less likely to transition to marriage even after accounting for the compositional shifts among individuals in cohabiting unions. Higher instability and decreased chances of marriage occurred among both engaged and non-engaged individuals, suggesting society-wide changes in cohabitation over time.

Evidence Unseen has collected some of the other studies together.

Excerpt

Hall and Zhao (from the University of Western Ontario) studied 8,177 individuals who were ever-married. They write, “Premarital cohabitors in Canada have over twice the risk of divorce in any year of marriage when compared with noncohabitors.”[13]

Manning (et al.) writes, “Over 50% of cohabiting unions in the US, whether or not they are eventually legalized by marriage, end by separation within five years compared to roughly 20% for marriages.”[14]

Daniel Lichter and Zhenchao Qian (from Cornell University and The Ohio State University) write, “If serial cohabitors married, divorce rates were very high—more than twice as high as for women who cohabited only with their eventual husbands.”[15]

And finally, there’s this study from Life Site News.

Excerpt:

Couples who reserve sex for marriage enjoy greater stability and communication in their relationships, say researchers at Brigham Young University.

A new study from the Mormon college found that those couples who waited until marriage rated their relationship stability 22 percent higher than those who started having sex in the early part of their relationship. The relationship satisfaction was 20 percent higher for those who waited, the sexual quality of the relationship was 5 percent better, and communication was 12 percent better.

The study, published in the American Psychological Association’s Journal of Family Psychology, involved 2,035 married individuals who participated in a popular online marital assessment called “RELATE.” From the assessment’s database, researchers selected a sample designed to match the demographics of the married American population. The extensive questionnaire included the question “When did you become sexual in this relationship?”

Couples that became sexually involved later in their relationship – but prior to marriage – reported benefits that were about half as strong as those who waited for marriage.

[…]Sociologist Mark Regnerus of the University of Texas at Austin, who was not involved in the study, responded to its findings, saying that “couples who hit the honeymoon too early – that is, prioritize sex promptly at the outset of a relationship – often find their relationships underdeveloped when it comes to the qualities that make relationships stable and spouses reliable and trustworthy.” Regnerus is the author of Premarital Sex in America, a book forthcoming from Oxford University Press.

Because religious belief often plays a role for couples who choose to wait, Busby and his co-authors controlled for the influence of religious involvement in their analysis.

“Regardless of religiosity, waiting helps the relationship form better communication processes, and these help improve long-term stability and relationship satisfaction,” Busby said.

Young men and women growing up really need to be informed by their parents what they are going to want to be doing long term, and what they should be doing today to accomplish those goals. Young people benefit greatly from the guidance of older and wiser people, but in defining goals and defining the steps to reach those goals. To be a convincing parent, you have to be convinced yourself. And to be convinced yourself, you need to be seen as having knowledge, not just opinions, but knowledge. Having the right peer-reviewed papers at hand will help you to be a better parent.