Definitions:

• Cohabiter: Someone who was earlier in a cohabitation relationship
• Spouse cohabitation: Premarital cohabitation with the same person as the spouse
• Only-spouse cohabitation: Spouse cohabitation and no other cohabitation
• Non-spouse cohabiter: Premarital cohabitation with someone else
• Spouse premarital intercourse: premarital intercourse with the spouse
• Only-spouse premarital intercourse: premarital intercourse with the spouse and nobody else
• Non-spouse premarital intercourse: premarital intercourse with a person other than the spouse

Booth and Johnson 1988 – Correlation between divorce and being a cohabiter.  Within three years, 5% of non-cohabiters divorced, and 9% of previous cohabiters did.  Correlation remains after controlling for various variables—all studies control for various variables.

Cohan and Kleinbaum 2002 – Correlation between poorer marital communication and being a cohabiter.  Correlation stronger for non-spouse cohabiters, but still present for spouse cohabiters.

Teachman 2002 (did not read) – Considers hypothesis that the cohabitation-divorce correlation was strong in the past and is now getting weaker, which would suggest a selection effect.  Hypothesis is not verified.

Teachman 2003 – More detailed study on women.   No correlation between only-spouse cohabitation or only-spouse premarital intercourse and divorce.  Correlation between non-spouse plus spouse premarital intercourse and divorce (multiplies annual risk of divorce by 2.2X).  Correlation between non-spouse plus spouse cohabitation and divorce (multiplies annual risk of divorce by 2.7X).   

Hewitt and de Vaus 2009 – Compares more recent against older marriages in Australia.  Cohabitation is becoming more common and more expected, and so we would expect changes in statistics.  Overall, there is a correlation between spouse cohabitation and separation/divorce.  However, that correlation gets smaller and perhaps disappears for the most recent marriages.  Some data, of unclear validity, suggests that there may even be a negative correlation for the most recent marriages.

Tach and Halpern-Meekin 2009 – The correlation between spouse cohabitation and lower reported marital quality is explained by the fact that more of the spouse cohabiter women had a birth before marriage.  Surprisingly, the correlation between lower marital quality and a birth before marriage disappears if the child’s father was not the future spouse when all factors, such as demographic ones, are controlled for.  On the other hand, the correlation remains in the case where the child’s father is the future spouse.  Marital happiness declines for everybody, and it seems like it declines at roughly the same rate.