Living together, however, invariably leads to sexual intimacy. God's plan for marriage and human sexuality as well as data from research suggest that cohabitation not only harms the preparation of a couple for marriage but also it corrodes the sacredness of marriage and the marital act and it corrupts its inherent meaning. The National Institute for Healthcare Research reported that couples who lived together before marriage have less satisfaction in their marriage than other couples. Although some may argue that living together before marriage is a way to prepare for marriage, the statistics show it is one of the worst ways. It is intimacy without exclusivity.
Sex needs to be elevated by marriage to be truly intimate, exclusive, and, ultimately, meaningful.
An obvious problem with cohabitation is its temporary nature. A trial is not marriage because marriage is permanent. One cannot test his or her capability to live a permanent relationship by diving into a temporary one. Psychologist Matti Gershenfeld surveyed 100 couples who cohabited and then divorced within five years. According to the study, few of these couples discussed key topics such as children, careers, and finances.