14. Successful cohabitation doesn't always mean a smooth marriage.
"It can be a great way for a couple to find out how compatible they are, and in some ways it can be an indicator as to what they could expect, should they go further and get married," McGrail says, "However, as I mentioned, I have found through experience that regardless how long a couple lives together, the second they get married, there is a change in the energy." An official, legal commitment like marriage will definitely change things, whether it's for the better or for the worse. Living together before marriage is a great indication of compatibility, but it is not a perfect picture of how marriage will be. "A lot of times, people can kind of hold it together for a year or so. They can be on their best behavior," Alpert adds. If cohabitation is smooth sailing, it's probably good news, but don't rely on that experience entirely.