Most of us have heard it taught that "Christ and the church" is a metaphor for marriage. We look at a human marriage and then look to Christ and His bride as an example.
John Piper (although I do not have a direct link) has put it in the opposite: Marriage was created by God (true) for the benefit of humans (true) in part as a metaphor to illustrate to the world the picture of Christ and His bride (not so clear).
One thing is clear (to me) - the parallel of husband and wife to Christ and the church is written in Scripture often enough for me to believe there is a significant lesson to be learned.
Which way does the metaphor run? I think perhaps both ways.
I believe that God is eternal and omniscient. He knew from eternity what man would bring and He knew the metaphor that He would inspire in Scripture. Do we really think that the "Christ and the church" idea was a sudden revelation to God? Of course not. I believe that the parallel between God/Israel and Christ/the church were there from eternity - before creation.
I believe that they are intertwined - a person can learn about marriage by looking at God's relationship with Israel and Christ and the church...and the world should be able to look at a Christian marriage and see it reflect Christ and the church.