4. When Love and Lust Collide
We mentioned above the pure air of first adolescent love. Unfortunately sexual attraction finds it more and more difficult to keep breathing that air. Love needs to be very strong indeed if it is to remain pure and delicate, generous in gift and not grasping in possession - even when, ultimately, it has the right to possess. This applies to the whole of premarital friendship between the sexes, to courtship, and to marriage itself.
Normal friendship between a teenage boy and girl can only be sincere and grow if they are on guard against lust. When the attraction between a boy and girl or a young man and woman takes the form of a more particularized love, then it is even more important to keep love free from lust. Clarity of mind and firmness of purpose are needed to achieve this. If love is sincere, there is little difficulty in noting the issues or differences that may arise. On the one hand, the indiscriminate instinct of lust with its promptings to seek satisfaction with the first appealing person available; on the other hand, there is the particularized human instinct (the conjugal instinct already present) urging to keep the gift of sexuality for one, and to respect that one when found before there is a mutual conjugal commitment. No one will say that this instinct of respect is easy to follow; but if true love is there, the instinct too will be there.
Let us consider now the union of man and woman in marriage,[71] which is the fullest setting for human love. It is in marriage that the collision of love and lust can be most dramatic, with so much depending on its outcome. We recall the title - "Marriage under the regime of sin" - under which the Catechism insists that the harmony and ease of the original communion between man and woman have been ruptured by a "disorder [that] we notice so painfully": the disorder of concupiscence which takes over when mutual sexual attraction, instead of being filled with respect and love, is "changed into a relationship of domination and lust" (1607).
Here our thoughts go naturally back to Augustine and to the terms in which he described this disorder: the evil of lust that spouses need to "use well" (i.e., to turn to good use), but which can frustrate and separate them if they use it badly. Augustine's view is nuanced and complex, but our reflections may help us see that it is neither pessimistic nor characterized by an anti-sex spirit.[72] One might perhaps give a modern 'personalist' expression to his view by saying that spouses use the sexual attraction between them well when, through constant vigilance, they raise it to the level of conjugal vitality and keep it there; and they use it badly when they let it decline toward the level of mere animal mating.
The contemporary magisterium insists time and again that each human being must be treated as a person and never as a thing. This is a rule for all human relationships, but for none as much as marriage. The conjugal instinct - as we have called it - wants to relate to one's spouse as to a person, never just as to a mere object to be used for one's own physical satisfaction. Carnal con-cupiscence, on the other hand, also present in marriage, tends in its self-centered forcefulness to disturb the loving relationship that should exist between husband and wife, and so can easily prevent marital sexuality from being completely at the service of love. Concupiscence wants to have and use the other person. Possession and satisfaction, not gift and union, are its concern. "In itself, concupiscence is not capable of promoting union as the communion of persons. By itself, it does not unite, but appropriates. The relationship of the gift is changed into the relationship of appropriation" (Theology of the Body, 127).