Let me tell you a secret: Living together prior to marriage decreases the likelihood of marital success. Don't take my word for it. Check the secular statistics. Couples who live together prior to marriage have five times as great a divorce rate as do couples who do not live together.
Co-habitation is not like marriage. It is not a binding relationship. It leaves the door open to separation. Marriage is different; it raises the commitment stake. It is, …for better or for worse until death do us part.
Most people in our culture think living together tests a relationship. Actually it is likely to produce false results.