The incomparable Fr. Neuhaus has a lovely blog post on the future of marriage over at First Things. It is mostly about questions of same-sex "marriage," but also on the post-modern metamorphosis of marriage into a private commitment between two people based on emotion.
He mentions a line from Dietrich Bonhoeffer, "who wrote to a young couple getting married that it is not only their love that will sustain their marriage but also their marriage that will sustain their love." This hits the nail on the head. How many times have you heard a divorce justified because "we just don't love each other any more"? That is to say, "we have ceased to feel loving at a level of intensity that we feels makes worthwhile the continuance of life together."
But of what value is a marriage if the vows, made in perhaps (perhaps not) a time of intense emotion, do not mean what they say: "In good times and in bad, in sickness and in health..." Surely loving feelings will not carry us through sickness, months of forced celibacy, endless sleepless nights, infidelity, poverty, disfigurement... They will not. The marriage--the promise made before the God "who will not abandon you" and the Church, "the eternal bride"--will sustain the love. Perhaps not the feelings of love, although I'm told they usually return in the later years to those who persevere, but rather the love of self-gift and the Cross. The marriage will sustain the love. And, in moments of need and plenty, the love will strengthen the marriage.
Yet another "both-and" moment!