You never marry the right person
I quoted, or rather re-quoted, Stanley Hauerwas saying this after Andrew Cameron's ethics lecture last year on singleness and marriage, and here is an article by Tim Keller making the same point. I particularly liked the last couple of paragraphs:
The reason that marriage is so painful and yet wonderful is because it is a reflection of the Gospel, which is painful and wonderful at once. The Gospel is—we are more sinful and flawed in ourselves than we ever dared to believe, and at the very same time we are more loved and accepted in Jesus Christ than we ever dared hope. This is the only kind of relationship that will really transform us. Love without truth is sentimentality; it supports and affirms us but keeps us in denial about our flaws. Truth without love is harshness; it gives us information but in such a way that we cannot really hear it. God’s saving love in Christ, however, is marked by both radical truthfulness about who we are and yet also radical, unconditional commitment to us. The merciful commitment strengthens us to see the truth about ourselves and repent. The conviction and repentance moves us to cling to and rest in God’s mercy and grace.
The hard times of marriage drive us to experience more of this transforming love of God. But a good marriage will also be a place where we experience more of this kind of transforming love at a human level.
(Excerpt from THE MEANING OF MARRIAGE © 2011 by Timothy Keller with Kathy Keller.)