From The Art of the Commonplace: The Agrarian Essays by Wendell Berry:
What marriage offers – and what fidelity is meant to protect – is the possibility of moments when what we have chosen and what we desire are the same. Such a convergence obviously cannot be continuous. No relationship can continue very long at its highest emotional pitch. But fidelity prepares us for the return of these moments, which give us the highest joy we can know; that of union, communion, atonement (in the root sense of at-one-ment)…
To forsake all others does not mean – because it cannot mean – to ignore or neglect all others, to hide or be hidden from all others, or to desire or love no others. To live in marriage is a responsible way to live in sexuality, as to live in a household is a responsible way to live in the world. One cannot enact or fulfill one’s love for womankind or mankind, or even for all the women or men to whom one is attracted. If one is to have the power and delight of one’s sexuality, then the generality of instinct must be resolved in a responsible relationship to a particular person.
Similarly, one cannot live in the world; that is, one cannot become, in the easy, generalizing sense with which the phrase is commonly used, a “world citizen.” There can be no such think as a “global village.” No matter how much one may love the world as a whole, one can live fully in it only by living responsibly in some small part of it. Where we live and who we live there with define the terms of our relationship to the world and to humanity. We thus come again to the paradox that one can become whole only by the responsible acceptance of one’s partiality.