A new study has listed 70 ways boredom can kill a marriage, with women more likely to lose interest in the relationship than men.
The research showed that while men are more likely to be bored with a partner outside of marriage, for those couples who had tied the knot the roles reversed.
For the study, 88 couples, including one who had been married for 36 years, were asked about their relationship. The answers included nearly 70 varying descriptions of boredom.
A second group of people were then given a list of these descriptions and asked which ones they identified with in their own relationships.
A relationship being "dull" was the most commonly picked answer, with lack of fun, lack of conversation and lack of romance also scoring highly, and "the relationship feels like a chore" was also a popular pick.
Some complained that the "butterflies" they had once felt in their stomach had vanished, while others felt they were in their partner's shadow.
A third experiment showed that this checklist, or 'Relational Boredom Scale' was specific enough to pick out relationship boredom from general boredom or depression.
The research also revealed marriage to be more boring than dating - and not just because of the amount of time spent together.
"Those who are dating might experience less boredom because they can more readily extricate themselves from a relationship once boredom sets in," the Daily Mail quoted researcher Beverley Fehr, of the University of Winnipeg in Canada, as saying.
"If a close relationships researcher were to approach people on the street and ask, 'What is the major obstacle to lasting love?' we suspect that the most frequent answers would be 'conflict', 'betrayal', 'selfishness' and the like.
"We would be quite surprised if anyone replied 'boredom' and yet that may be the correct answer - or at least one correct answer," Fehr added.
The article has been published in the journal Personal Relationships.