If it were really true that living together is a trial of marriage, then divorces would be more common among couples who hadn’t first lived together than among couples who had. Actually, just the opposite is true: Divorces are more common among couples who have lived together first than among couples who haven’t. The reason isn’t hard to find. The very essence of marriage is having a binding commitment. The very essence of living together is having no binding commitment. That’s why living together can’t be a trial for marriage, because in everything that matters, the two conditions are opposites. And that’s why not having a binding commitment is less like training for marriage than like training for divorce.