The average duration of the first relationship was 38
8 months, while the average duration of the second was 29.6 months. Thus, the relationships studied were mostly serious and of substantial duration. No one was married at the start of the project, but some would have married that first partner or the second during the time frame of the study. For the most part, however, it is best to think about these findings in the context of the stage of life in which people are often seriously involved, but not yet married-a stage of life that has grown substantially in the past few decades.
At each time point (which tended to be every four-to-six months), participants were asked, “Have you had sexual relations with someone other than your partner since you began seriously dating?” Participants were also asked if they had either known or suspected their present partner of having sex with someone else.