In a recent article on Fox News.com, they referred to a study done by Journal of Family Psychology in February studying those who lived together outside of marriage: check it out.
I will not discuss it further than to say...why do we assume that God's Word is not true. We often will look to stats, logic, and popular opinion before God. Even when the stats line up with God's Word, we still don't want to listen. We all need to repent of this mindset.