Married couples who watch pornography almost double their risk of divorce, researchers claim.
While it was once seen as the preserve of husbands, it now seems that wives are almost as keen on watching it as men.
But viewing adult films or images comes at a price, with the researchers saying that women who start looking at porn while married are almost three times more likely to want a divorce.
Their report comes after statistics last year showed that as many as one in three women watches adult content at least once a week, with the majority viewing it on their mobile phones.
In the latest research, sociologists from the University of Oklahoma interviewed thousands of married adults regularly over several years.
They found that porn negatively affects those in a happy marriage, the newly married or those from a non-religious home.
But there was no increase in the probability of divorce among weekly church-goers because the social stigma of divorce was greater, showing "religion has a protective effect on marriage, even in the face of pornography use".
Assistant professor Dr Samuel Perry, who collected the data as part of the General Social Survey, said: "Beginning pornography use between survey waves nearly doubled one's likelihood of being divorced by the next survey period, from 6 per cent to 11 per cent, and nearly tripled it for women, from 6 per cent to 16 per cent.
"Our results suggest that viewing pornography, under certain social conditions, may have negative effects on marital stability." Those who were "very happy" in their marriage were associated with a noteworthy increase - from 3 per cent to 12 per cent - in the likelihood of getting divorced by the time of the next survey.
But viewing pornography had no effect on unhappier marriages, according to the study. Dr Perry added: "We took this to mean that pornography use - perhaps if it's discovered by one's spouse unexpectedly - could rock an otherwise happy marriage to the point of divorce, but it doesn't seem to make an unhappy marriage any worse than it already is."
Men whose wives watch porn may be encouraged by the news that if she stops watching it, the probability of getting divorced dropped to 6 per cent among the couples interviewed. But if she decides to continue, the risk of divorce remains at 18 per cent.
And there was no effect on divorce rates among men who stopped watching porn. Dr Perry said that despite the findings, presented at the American Sociological Association, he was not trying to make people stop watching adult material.
"We have no desire to push a 'ban pornography' agenda on the grounds that it can be harmful to marriages," he said.
"We think information is helpful, and [people] should be aware of the potential consequences of pornography under certain circumstances."
Last week, a psychosexual therapist at Nottingham University Hospital said that online pornography is damaging the sexual health of young men. Angela Gregory said they are increasingly likely to suffer erectile dysfunction because they are unable to be aroused by normal sexual behaviour.