There are many predictors of the success of a marriage, among them the having of money, the having of children, and the length of time a couple spends dating before they tie the knot.
Another big predictor, though, is age: The closer a couple is when it comes to their respective birth years, the greater their chances of avoiding divorce.
A study released in 2003 by the United Kingdom's Office for National Statistics concluded that the proportion of women in England and Wales marrying younger men rose from 15% to 26% between 19.
The study also showed a higher divorce rate as the age difference rose when the woman was older and a lower divorce rate as the age difference rose when the man was older.
Age-disparity relationships have been documented for most of recorded history and have been regarded with a wide range of attitudes dependant on sociocultural norms and legal systems. Relationships with age disparity of all kinds have been observed with both men and women as the older or younger partner.
In various cultures, older men and younger women often seek one another for sexual or marital relationships.
The “half your age plus seven” rule of thumb probably helps you avoid being a creep, but is it accurate?
Much to my surprise, when overlaying a line representing the rule of thumb on Kenrick and Keefe’s results (see red line in the figure below), you can see it closely matches the low end of the range (i.e., youngest preferred) for all but the oldest men.
And a 10-year difference makes them 39 percent more likely.
Men, in contrast, are hypothesized to be most attracted to women in their reproductive prime, which tends to be when they are younger. Women’s preferences, on the other hand, hold relatively constant across their lives, not going more than a few years below their own age (extra-credit if you can identify the "cougar zone" in this figure), but women remain keen on men up to 10 years older than themselves. However, younger men (i.e., in their 20’s) tend to be married to someone of a similar age, but as they get older their wives get younger.
For example, by their 50’s the average male has a wife who is 10 years younger than him.
A common rule of thumb, at least on the internet, is that it’s okay to be interested in someone “half your age plus seven” years.
According to this rule, it would not be creepy for a 30 year old to date a 22 year-old, but an 18 year-old would be off-limits.