from Psychology today:
6. Do you want to test out your relationship first by living together?
It's common for contemporary couples to live together before marriage, but their reasons for doing so appear to predict how happy their marriage will eventually be. When couples use cohabitation to test out a relationship, or when they cohabitate for practical reasons (e.g., finances), they tend to report less dedication to their relationships and less relationship confidence. Should their arrangement transition to marriage, these initial uncertainties could help explain why cohabitation before marriage sometimes leads to lower marital satisfaction (Kamp, Cohan, & Amato, 2003). Couples that are already highly committed, and cohabitate for other reasons — e.g., to spend more time together — might be better poised to move towards marriage.
6. Do you want to test out your relationship first by living together?
It's common for contemporary couples to live together before marriage, but their reasons for doing so appear to predict how happy their marriage will eventually be. When couples use cohabitation to test out a relationship, or when they cohabitate for practical reasons (e.g., finances), they tend to report less dedication to their relationships and less relationship confidence. Should their arrangement transition to marriage, these initial uncertainties could help explain why cohabitation before marriage sometimes leads to lower marital satisfaction (Kamp, Cohan, & Amato, 2003). Couples that are already highly committed, and cohabitate for other reasons — e.g., to spend more time together — might be better poised to move towards marriage.