In short it is a relationship term - usually after 7 years people tend to re-evaluate their relationship. There might be evidence that it is now much shorter but the original number 7 came from a time period where the average marriage only lasted 7 years.

There is also speculation that this might be a real itch related to skin condition, insects, or STDs. All along you saw signs but you ignore them or you were too busy to act on them, and after seven years you finally realized what you missed and try to change it. Supposedly, after being married for seven years or just being with someone for that long, you start looking at other options. Hence you have an itch to scratch. In laymans terms, one is expected to leave/cheat at this time. A recent question on Hollywood sq. showed that statistics reveal the average marriage in North America lasts 7 years. maybe thats where it comes from, mine this year is 32, (where did we go wrong.) It use to be the seven year itch, but it has drastically lowered to anywhere from six months to four years. People just dont seem to rate marriage on the high end these days and if there is a problem in the marriage (there will always be that bridge to cross no matter how wonderful a marriage we have) one of the two will often walk away instead of sticking it out through some of the bad times. Sadly, divorce is at a much higher rate. TWO-YEAR ITCH INFECTS MARRIAGE COUPLES watching out for the seven-year itch should be on their guard a lot earlier these days. According to research, they are far more likely to separate after about two years of marriage. One in 12 couples is heading for the divorce courts after 24 months - more than double the figure for seven years. The seven year itch statistic refers to the number of years together when the most divorces happen. So the first person was right. The seven-year itch refers to the itch to break up. According to the US Census Bureau, this statistic has slowly inched toward 8 years. So now we have an 8-year itch to scratch. According to most researchers, divorce statistics are the most abused. One of the reasons why we have an increase in divorce statistics is not shorter relationships, but longer lives. Another reason is because divorce statistics never measure abandonment. For example, divorces were low during the Great Depression, the 1930s, because it was cheaper and easier to simply leave. So it shows a decrease in divorces because they dont measure abandonments. Ideally, we would study relationships and include marriages, and we would study relationship endings, not just divorces. The seven year itch is an odd term for a small mite that lives under the skin, also called scabies. It causes severe itching beginning in the wrists and feet. They call it the seven year itch because it is very difficult to get rid of. The Seven Year Itch is not a relationship term. It is also not a mite. This term refers to eczema, a skin condition usually being a rash, which is extremely itchy and aggravating. I personally have this chronic rash, and it can last for a short length of time or a very long stretch of time such as seven years. Not everyone has it for seven years, so its more of an expression that people dont understand and apply it to what they think is correct. The Seven Year Itch is a Classic Comedy starring Marilyn Monroe and Tom Ewell. The 20th Century Fox film was an adaptation of the Broadway play of the same name by George Axelrod. It was directed by Billy Wilder and presented in Deluxe Color CinemaScope. Often cited as one of the great comedies of its time, it won critical acclaim and became the biggest box office hit in the summer of 1955. It contains one of the most iconic images of the 20th Century in which Marilyn Monroes dress is blown up above her waist by a passing train underneath a subway grate she is standing on. Males tend (in my observations - and in hindsight) to have three and a half years relationship cycles (that is they re-evaluate the relationship every three to four years generally) whilst females tend to have the so-called Seven year itch (with all due respect). This is partly due to the nesting instinct, and partly due to their innate patience. (I would say infinite but it seems there is a limit - take note gentlemen, thus, divorces or breakups found at between three to four years and 11-12 years are typically initiated by the male, with the majority of breakups occurring at around seven years where the psychological security of the relationship is at its ebb. This being said, one also has to factor in the females nesting instinct could have an impact on a females choice regarding divorce or breakup - certainly if children were introduced into the relationship whether it is due to deep-rooted (pardon the pun) sexual motives (such as both sexes desires to procreate/nest vs hunt) or otherwise is a matter of further discussion. If it is due to a conjunction of male-female re-evaluation phases then, obviously, at seven years perhaps it is natural that breakups would occur more readily. According to the news on T.V. 51% of Canadian couples live together so married couples are now the minority. It was my understanding the term referred to the STD herpes; which although incurable outbreaks tend to decrease in frequency significantly after about seven years. It would be pertinent to find out how long this phrase has been in use, as well, as its cultural origins.