'The Church does not impose on us the idea that love should be permanent. Permanence is what the heart longs for. In her teaching that sex is meant to express permanent love (that is, marital love), the Church is simply inviting us to be true to the "song" that wells up from the deepest recesses of our souls. Listen to it! It is the Song of Songs.'
Christopher West, Theology of the Body for Beginners, p.101.
