In Catholic theology, God is the ultimate end of Man. The created order, with all its good and beauty, can be understood as a sign that points to God.

Marriage under a Catholic understanding has both a natural and a supernatural end. The natural end is procreative, but the supernatural end is that of a friendship in which husband and wife help each other on their journey toward Heaven.

In Dante, we see Dante's love of Beatrice lead him to God. He never marries her, but through her beauty and his love of her, she becomes a kind of icon through which Dante is led toward virtue and the divine. Eros draws him upward, but he is purified by agape. Agape purifies eros. The willing of the good of the other, self-sacrifice, surpass the satisfaction of one's desires and purify them.

(Incidentally, this is why, in this theological light, vile perversions like pornography become even more horrifying and dark. There is a sense in which one is also participating in an act of desecration.)