God has a plan for the World, and marriage is at the heart of it. That's why He said "it's not good for a man [or Adam] to be alone. I will make a helper corresponding to Him..."
That's why God made Adam full of desire and Eve so amazingly beautiful. That's why He gave us the Seventh Commandment. That's why God chews out men who have "been faithless, though she is your companion by covenant." (Mal. 2:14) God goes on to ask, "did he not make them one, with a portion of the Spirit in their union...guard yourselves in your spirit, and let none of you be faithless to the wife of your youth."
I for one think God's plan is a pretty good one. He make them one, and mysteriously multiplies them as "Little Imagebearers" come into the picture. Announcement to all -- we are expecting Number Three in early May!
The key in this whole picture is God. Without him, you've only got 50/50 performance relationship. With Him at the center -- you've got a transformational commitment that will make you more like the Savior. Have your way in our families, O LORD God!