In 2016, thousands of couples across Europe will decide to move in together—without getting married first. It makes sense. Sharing expenses cuts costs in an economy characterized by sluggish wage growth, and living together simply saves time. Plus, cohabitation connotes a certain level of commitment without the legal—and social—obligations that come with marriage. You might call it a baby step. Whatever the case, they won’t be alone. By 2010, nearly 40% of French couples between the ages 25 and 44 had chosen the cohabitation route, registered or unregistered.