The best marriages are those where women marry men who are less attractive than themselves, research has found.
Psychologists who studied newlyweds found men who were better-looking than their wives were more likely to be unhappy and have negative feelings about their marriage.
In couples where the wife is more attractive, both partners tended to be very content.
The research, published in the Journal of Family Psychology, suggests that, in evolutionary terms, women are less choosy about their man's looks as long as he is able to help them reproduce.
Men, however, are programmed to choose a mate who is most likely to pass on their genes and look for youth, health and physical attractiveness.
The tests involved 82 couples married within the previous six months.