For decades, women have been faking headaches or tiredness when they’re not in the mood.
So it will come as no surprise that a third of them say they are less interested in sex than their male partner.
But those who often tell their other half "I’m too tired tonight" are no more unhappy in their relationships, a study has found.
Sociologists said that modern women accept that men wanting sex more than them is just "part and parcel" of a normal relationship.
Following a survey of 5 000 people in relationships aged 16 to 65, researchers from the Open University and Huddersfield University found that couples who can talk about the difference in their sex drive are the best at carrying on regardless. Professor Jacqui Gabb, of the Open University, said: "What’s really interesting is that couples are saying that differences in sexual frequency and desire are just part and parcel of the relationship cycle and are accepted as not particularly significant.
"What couples talk about is finding a compromise – other ways of sharing and expressing feelings, acknowledging issues and accommodating these and, for older couples especially, not taking it all too seriously."
Almost two-thirds of couples say sex is an important part of their relationship, but 33 percent of women agreed with the statement that their partners wanted sex more than they did.
At the start of a relationship this was the case for only one in five women. But after 16 years together, almost half of women found their sex drive had fallen below their partner’s.
Professor Gabb said: "Men reported they wanted to have sex more frequently, while women wanted it less often, and we saw that some men thought about sex in a different way.
"For some men, sex appeared to feature as something that was done for them by their female partners rather than something that was shared between the couple."
The findings were presented to the British Sociological Association’s annual conference in Manchester.