Democrats are less inclined than Republicans to cheat on their spouses, according to researchers who matched voter records to accounts hacked from a US website that specialises in extramarital affairs.

The study of 80,000 voters in five US states found that Democrats used the Ashley Madison adultery website substantially less than Republicans, Libertarians, Greens and unaffiliated voters. Libertarians consistently ranked as the site’s most frequent clients.

The results highlight an apparent paradox where those with more conservative views and supposedly stricter attitudes towards sex seem happier to hop into bed with someone outside their relationship than more liberal types.

“Our results are perhaps the strongest evidence yet that people with more sexually conservative values, although they claim to act accordingly, are more sexually deviant in practice than their more sexually liberal peers,” the researchers write in Archives of Sexual Behaviour.

Kodi Arfer, a behavioural scientist at the University of California in Los Angeles, and Jason Jones, a sociologist at Stony Brook University in New York, linked the 2012 voter registration records for California, Florida, Kansas, New York and Oklahoma to credit card payments made by people living in those states to Ashley Madison between 2008 and 2015. The payment details were released in 2015 when a group called the Impact Team hacked millions of Ashley Madison accounts.

Of the five states looked at in the study, California had the greatest proportion of Ashley Madison users, with one in 560 voters holding an account. But in this state, political allegiance was only marginally linked to who signed up, with Libertarians making up one in 250 account holders and Democrats making up about one in 700. The rest all fell in between.

According to the study, the smallest percentage of the website’s clients lived in Oklahoma, where only one in 943 voters had made payments to the site. But the state, which has backed a Republican in every presidential election since 1968, boasted the greatest political split in users, with fewer than one in 1,500 Democrats holding an Ashley Madison account compared with one in 700 Republicans.

Across the board, Libertarians made up the greatest proportion of Ashley Madison clients. In the four states that had Libertarians, namely California, Florida, Kansas and New York, about one in 250 of the site’s clients had registered as Libertarians.

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The study does not shed light on why Republicans might be more likely to have affairs than Democrats, but Arfer has a couple of theories. The first is that, thanks to more restricted sex education and discussion, right-leaning people may be less well-informed about sex and sexuality, and so have poorer sexual self-control. The second is that people who are more interested in taboo activities declare themselves Republicans, and profess to have stricter attitudes, to deflect suspicion.

But another explanation is possible. Political party allegiance may simply be a proxy for wealth, and Republicans tend to be better off than Democrats. “It stands to reason that wealthier people should be more likely to use Ashley Madison, which can be expensive,” Arfer said. “So the party effect we observed could be driven by income instead of, or in addition to, ideology.”

There is always the possibility that some Ashley Madison clients are plunged into turmoil by the realisation that their behaviour is in direct conflict to the standards they hold most dear. For such people, the authors have some suggestions that may help. “Such a person either needs to change his behaviour or change his values,” said Arfer. “That’s easier said than done, but simply learning more about human sexuality could help, particularly if my hypothesis about worse sexual self-control is right.”