In the real world, adultery is painful and traumatic to couples who suffer from it, and their marriages either reach a hard-won reconciliation or are destroyed by it.
But countless modern movies like American Beauty ask the audience to understand — and even applaud — adultery. The typical story line goes like this: A stifling marriage has left a husband or wife (or both) unsatisfied. It is often suggested that the adulterer-to-be has made great efforts to bridge the gap between the two. Often, the other spouse is uncaring or unkind. The adultery, when it occurs, is perfectly understandable. Why be true to an uncaring or unfeeling person? How is a marriage worth fidelity when love has left it?
The Catechism of the Catholic Church recognizes how “easy” adultery can become when a couple have already parted ways in their hearts. That's why, in speaking of marital fidelity, it points toward true romance: “St. John Chrysostom suggests that young husbands should say to their wives: I have taken you in my arms, and I love you, and I prefer you to my life itself.
For the present life is nothing, and my most ardent dream is to spend it with you in such a way that we may be assured of not being separated in the life reserved for us …. I place your love above all things, and nothing would be more bitter or painful to me than to be of a different mind than you” (No. 2365).
The Catechism then points out that adultery is “an image of the sin of idolatry,” an “injustice” to one's children, a transgression against the rights of the spouse and an attack on the marriage bond (No. 2381).