The seven-year itch is a
psychological term that suggests that happiness in a relationship declines after around year seven of a
marriage. The phrase originated as a name for irritating and contagious skin complaints of a long duration. Examples of reference may have included
STD outbreaks that are known to significantly decrease in frequency after seven years, or mites that live under the skin (
scabies) and cause severe itching that is hard to get rid of. Later on in the 19th and early 20th centuries it was viewed as an expression of imagined appropriate punishment for
antisocial behavior, or as a simile for a situation with little hope in relief.