Most love cheats have three affairs before their cheating is discovered by their partners, according to a new survey.
And it takes an average of four years for their adultery to be exposed - most commonly through their partner reading their phone messages.
The vast majority of people (86%) who cheat on their spouses after marriage have already slept with another lover before tying the knot.
The results are from a new survey of 1,000 adulterers by IllicitEncounters.com, the UK’s leading dating site for married people.
It discovered clear patterns of behaviour suggesting that if a person is unfaithful early on in a relationship they will continue to seek affairs after marriage.
Two-thirds of adulterers (63%) have been caught out by their partners at some point in their marriage.
But this lead to the break-up of the relationship in only 15% of cases.
Most people are prepared to forgive one sexual liaison if other elements of their relationship with their partner are strong.
Cheats tend to be extremely careful not to get caught with a lover straight after they have tied the knot.
Just one in 10 adulterers (11%) were caught during their first affair after matrimony and one in eight (12%) during their second.
The most common time for an affair to be exposed was during the third affair with one in five (21%) saying this was when they were caught out.
The main reason was that adulterers tend to get more brazen the longer they get away with cheating and they are not as careful at covering their tracks.
The most common ways cheats are caught out are - partner reading phone messages (39%), partner reading emails (22%), being caught lying about their whereabouts (20%), being spotted out with a lover (14%), being informed on by a family friend (5%).
IllicitEncounters.com spokesman Christian Grant said: “What this new research shows is that a leopard never changes their spots.
“If your partner is unfaithful to you before tying the knot that pattern of cheating will continue after matrimony.
“Cheats need to be extra careful around the time of their third affair because this is when they are most likely to get caught - probably because they have got over-confident and give too many clues away to their partner who will be getting suspicious.
“It is interesting that an affair leads to a break-up in only 15% of cases.
“Most people are prepared to forgive an affair if the fundamentals of a relationship are strong and we have a lot of members at IllicitEncounters.com who have permission to have affairs because their partner has gone off sex.
“As a nation, we are becoming a lot more like the French who often see an extra-marital affair not as a reason for divorce but the natural reaction to a relationship going stale.”
Every week, around 20,000 people in the UK are having affairs on IllicitEncounters.com.
More than one million people have registered with the site since it started in 2003 and the highest proportion of members are wealthy people in London and the Home Counties.
Top 5 ways affairs are discovered
1 Phone messages to lover discovered by partner (39%)
2 Emails to lover discovered by partner (22%)
3 Caught lying about whereabouts (20%)
4 Being spotted out with lover 14%)
5 informed on by friend of partner (5%)