Jay Teachman, an academic, investigated this matter further. The study, which is available online, makes for interesting reading. Teachman's genius was to look stratify the cohabitors risk of divorce by the by the number of sexual partners/cohabiting history.
The study was based on data from the National Survey of Family Growth 1995 cycle and involved over 6500 women.
It was controlled for a host of variables.
The study was in no way sponsored or funded by any conservative organisation.
The results presented in this article replicate findings from previous research: Women who cohabit prior to marriage or who have premarital sex have an increased likelihood of marital disruption. Considering the joint effects of premarital cohabitation and premarital sex, as well as histories of premarital relationships, extends previous research. The most salient finding from this analysis is that women whose intimate premarital relationships are limited to their husbands—either premarital sex alone or premarital cohabitation—do not experience an increased risk of divorce. It is only women who have more than one intimate premarital relationship who have an elevated risk of marital disruption. This effect is strongest for women who have multiple premarital coresidental unions. These findings are consistent with the notion that premarital sex and cohabitation have become part of the normal courtship pattern in the United States. They do not indicate selectivity on characteristics linked to the risk of divorce and do not provide couples with experiences that lessen the stability of marriage.Executive summary: It's not the liberal values, it's the number of partners that matter.
This limitation notwithstanding, the results presented here should shift attention away from research that focuses on the selection of individuals into cohabitation and premarital sex to a focus on the selection of individuals who do not marry the individuals with whom they first cohabit or initiate first sex. It may well be the case that, irrespective of the legal status of the relationship, the relevant distinction to make is between people who form multiple relationships and people who form a single, longer lasting relationship.The paper data and methods can be found here. Premarital Sex, Premarital Cohabitation, and the Risk of Subsequent. Marital Dissolution Among Women
Oh, in table 4 of the study, Teachman gives probabilities of divorce, which for fun, we will map onto the Heritage Foundation's study.
10 year divorce rate of the Teachman study group was 34%. (I didn't use the 5 year divorce risk in Teachman's paper since the Heritage study made its calculations on the people being married more than 5 years)
Teachman didn't plot the risk by the number of sexual partners, merely that more than one and in different relationship contexts, so I have simply marked the range of his findings. Note, the really disturbing one still holds. A soon as a woman has had more than one partner her long term marital stability risk drops to near 50%.
Note: Statements reproduced from the Teachman paper are not believed to violate copyright under the fair use clause. Any violation is unintentional and offending material shall be removed immediately if it violates any repespective laws.