Search for how common infidelity is in Australia and you will find numbers everywhere. Twenty five per cent. Forty to seventy per cent. Sixty six per cent. They appear on counselling sites, law firm blogs, news articles and, until recently, on some of our own pages.
Follow any of them back far enough and the trail goes cold. There is no Australian study that measured how many Australians have been unfaithful. Not a dated one, not a small one. It has not been done.
What gets mistaken for one
The most commonly cited Australian source is Relationships Australia’s research on infidelity, a survey of around 1,800 visitors to its website. It is real research from a credible organisation and it is worth reading. But look at what it asked. It asked people what they think causes infidelity and how common they believe it is among other people. Most respondents pointed to emotional disconnection as the main cause.
That is a perception survey. It tells you what Australians believe about infidelity. It does not tell you how many Australians have committed it, and the two are very different kinds of data. Perceptions of how common a behaviour is tend to run well above the measured rate, for almost any behaviour you care to name.
When a site quotes “Australians say infidelity is common” as though it were “this many Australians cheat”, the error has already happened. Most of the wilder Australian figures in circulation are that error, repeated.
The other source of Australian statistics: they are not Australian
The rest are imports. An American or British figure gets quoted on an Australian page, the country of origin drops off somewhere in the retelling, and a few links later it has become an Australian statistic. Once that has happened there is nothing in the number itself to give the game away.
The giveaway is usually elsewhere. Units are a good tell. We found a table on one of our own group’s pages that reported average distances in miles. Nobody in Australia measures a surveillance job in miles.
What we quote instead
One figure, correctly worded and correctly attributed.
A US Institute for Family Studies analysis of General Social Survey data found that 20% of married men and 13% of married women reported having sex with someone other than their spouse while married.
Three things about how that sentence is built, because the details are where these claims usually go wrong:
- It says US. The General Social Survey is American. We are not going to pretend it is Australian.
- It says married men and women, not men and women generally, because that is the population the figure describes.
- It says reported having sex with someone other than their spouse while married, not “admitted to cheating on their current partner”. Those are different questions with different answers, and self-reported figures on a sensitive subject are near certain to understate the truth.
We previously had all three of those details wrong in places, including one page where the words “IF Studies” were linked to an entirely different website. That has been corrected.
What about divorce
Divorce is better served. The Australian Institute of Family Studies has published a cohort projection that roughly 40% of marriages will end in divorce, and it is the standard citation in Australian media. But it comes from a 1993 article, which makes it a dated thing to quote as a current fact.
The Australian Bureau of Statistics publishes the underlying counts each year. For 2025 there were 118,804 marriages and 49,158 divorces. Those are annual counts of different cohorts of people, not a lifetime rate, and dividing one by the other does not give you a divorce rate no matter how often you see it done.
We do not quote a divorce percentage on our sites. That is deliberate.
Our own numbers
The one statistic we own outright is our success rate, which we describe as around 95% based on our own client outcomes over 20 years. We say that qualifier every time, because without it the figure looks like published research, which it is not.
It also counts every matter that ended with the client having a clear answer, including the ones where a partner turned out to be faithful. We are not claiming 95% of clients discover an affair.
Why we are publishing this
Because the alternative is to compete on who can print the most alarming percentage, and that race has no bottom. If you are trying to work out whether your suspicions are worth acting on, the honest answer is that no national statistic can tell you. Only evidence about your own situation can.
