Cucking certainly is not confined to any one age group, as the variety of comments thus far indicates. It does tend to occur more, however, in middle-age and older groups. Some couples prefer (as in the comment above) to establish their family and have kids before branching out to new lovers. Some find in middle age that sex with each other has lost its spark, so they seek a new lover to ignite new passions. Often in middle age the husband begins to lose some of his virility and the woman needs more than he can provide. The list of reasons could go on, but those are three major factors.