Marriage is an institution that elevates us and ennobles us, that helps us aspire to a kind of greatness that we still—despite our attempts to obscure it—can glimpse today. We can always love another person. We can commit ourselves with the single-mindedness of devotion and discover that there are depths to ourselves and one another that we might never have known otherwise. Our marriages can get better—but only if we learn their meaning and begin to submit to their moral demands.

Treating same-sex and different-sex erotic relationships as equivalent removes from eros the glorious possibility that we might discover a love stronger than death, that a man and a woman might be so devoted to one another alone that they would form a community whose children would be icons of their exclusive, permanent commitment. That glorious aspiration and the hope of its fulfillment make us vulnerable to nearly infinite depths of sorrow and loss. But they also make the world a more exciting, dramatic, and beautiful place to live.

Matthew Lee Anderson, "Why I Am Opposed to Gay Marriage"