Once you are engaged and have committed yourself to the other person in front of God, why can’t you act married (sexually) before the wedding date? In my son’s mind he is totally committed to this young lady and vise versa and he feels that in God’s eyes they are already married so why can’t they act like it?
If you were to live in a time and culture where there was not a civil law aspect to marriage, then I believe that two persons who “agree” they are married before God with all good conscience, would indeed “be married”.
But that is not the case in America, or most of the world. Marriage is a civil contract that has to meet legal criteria to be recognized. God ordains rulers and governments (Matt. 22:17–21; Luke 20:25; Rom. 13:1–7; Tit. 3:1; 1 Pet. 2:13–17), so the laws concerning marriage must be obeyed by Christians so long as they don’t violate God’s Word.
The fact is, no matter how sincere, two people can call off a marriage right up until the second of saying “I do”. So “acting married” up until that point has no real binding affect regardless of how sincere people may be and is tantamount to fornication.
The consumation of a marriage, the speaking of marriage vows in front of friends and family, the signing of marriage licenses, etc – all serve to give an official stamp and finality to the covenant of marriage.
Once we start allowing people to “act as if” something is true, before it actually is, we will have opened Pandora’s box. That concession with regards to marriage would put us a breath away from simply “shacking up” before marriage.