Although I think co-habiting is not good preparation for marriage, this report doesn't cite enough sources, and some are old. That's not unusual for social science reporting. Although the study on differences of income was one I hadn't seen (co-habiting men earn less over a life time than married men, and often less than their housemate). My personal thought is the "finances" angle for co-habiting is phony; women are hoping for a transition to something more permanent and men are hoping for a few more months/years of less permanence. It is always about commitment, and about half don't want that so they settle for something less. I've never talked to a married woman who co-habited before marriage who said in hindsight that it was good for the marriage, even those that last. Small sample, of course.