There’s a general assumption – so widespread that it no longer requires demonstration – that in order to have a high-quality and lasting marriage, it’s necessary first to finish college, start a successful career, and then look for a partner with the same qualifications.
Despite the ease of divorce, marriage is still perceived as being characterized by exclusivity, fidelity, and permanence. As a consequence, another idea that has become a widely shared and promoted before embarking on such a definitive commitment is to give the relationship "a test drive" first -- a period of cohabitation -- to see how being together within the same walls works when you have shopping and chores to do, work commitments to juggle, and perhaps already a child to raise.