When somebody turns up after a divorce with a partner twenty years younger, the comment is ready before the sentence is finished. Midlife crisis, vanity, running from the mirror. The psychologist Lara Ferreiro argues that reading usually misses, and her explanation is more interesting than the gossip.

"Sometimes they are not really looking for a 'young person' - they are looking for a new version of themselves," says Ferreiro, author of the book ¡Ni un capullo más!. The distinction matters. In the first case it is about the other person's age. In the second, it is about who you want to be in the next phase, and the partner is simply the means of testing whether that version exists at all.

Her second argument is pure arithmetic. "At twenty-five you might be looking for the ideal father for your children, financial stability, a home and a family project. At fifty those needs are already settled." Once the list is closed, the criteria do not change on a whim - they change because the old ones no longer measure anything. What remains is far harder to quantify: who you find it easy to be in a room with.

What is actually being sought

Ferreiro points out that the key feeling is not the one everyone assumes. It is not only about feeling desired - it is about feeling heard and psychologically recognised. That is a different currency from attractiveness, and it depletes more slowly.

Her conclusion is carefully worded: a woman who falls for an older man after a divorce is not necessarily running from her own age, but may be moving towards a freer version of herself. The same logic applies in reverse, except that for men nobody bothers asking the question.

And that is the part worth holding on to. When a relationship ends after fifteen or twenty years, the person walking out of it usually has no idea who they are outside that role. The partner they choose afterwards is not a diagnosis - it is a first attempt at answering the question. Whether the answer is right is an entirely different subject, and one psychology has far less to say about than anybody would like.