Another common element of Swift's relationships is that of couples mismatched by age. Nowhere is this portrayed with greater contrast than in the short story "The Watch," where the husband, ageless thanks to the protection of a magical pocket-watch, is fast approaching his one-hundredth year as his wife approaches her fortieth. Their relationship works until the wife starts to want children.

A similar problem exists in "The Hypochondriac," and in the incestuous relationship between father and daughter in Waterland. But in Waterland there is an historical precedent for this type of forbidden love: the wedding of Thomas Atkinson to Sarah. "In short, Sarah Atkinson is in her prime; and her husband is growing old and doting -- and jealous." (Waterland p.57) A powerful and dangerous Love brings together these mismatched pairs, star-crossed and doomed to self-destruction. The one exception to this unhappiness is the relationship between Harry Beech and his fiancÚ Jenny, who is younger than his own daughter, in Out of This World. The love that they share makes Harry feel young again, in contrast to the above mentioned relationships where the youth of the wife serves only to make the husband feel even older.

The eventual downfall of married couples in Swift's work is the conflict between natural urges and the norms of society. Extra-marital affairs are common elements of nearly every marriage mentioned. When affairs do not actually exist, one partner usually suspects that one does. As Swift's philosophy of knowledge points out, perceived knowledge is equally as dangerous as known fact. Another common element is that most quarrels return to the question of a generation gap. Either the couple fights because of a difference in their ages or they fight over their children. As social value systems change to meet the modern age the elder generation has the most difficulty in keeping pace. The regular progression of time fates the end of these relationships.