Research has emerged that only children are more likely to cheat than someone with siblings.
Affairs dating site Illicit Encounters conducted a study ad found the majority of its users (34 per cent) are only children.
This is significant because the average family in Britain has at least two children, which means only children are over-represented on the site, The Sun online reports.
The people most likely to cheat after only children is the eldest sibling, with 28 per cent of cheaters on the website being first born in the family.
A further 23 per cent of the website’s members are the youngest, and 15 per cent are middle children, making them the most faithful.
The site also looked at the number of members with step-children and found 24 per cent have a step-sibling.
This could suggest their parents’ history of having multiple partners has rubbed off on them, according to a spokesperson for the website.
Christian Grant, said: “It’s well-known that an only child can experience the feeling of immense loneliness in their childhood, and that comes back to haunt them in their future relationships.
“Having been starved of attention for so long, it’s something that they find themselves in desperate need of.
“This manifests itself quite clearly when someone’s partner works long hours or travels frequently for work; the alone time for an only child just won’t do, so an affair is the perfect short-term solution.
“On the other end of the scale, a middle child is surrounded by loving parents and siblings. They don’t grow up with the same need of love and affection, but they’re also more than comfortable during moment of isolation.
“Step-siblings, too, are negatively influenced by their childhood. Having see their parents unable to remain happy with a single partner, it’s easy to see why they’re more susceptible to following suit.”
Another of the website’s studies revealed how long unfaithful lovers wait before they continue to play the field – and it’s not as long as you think.
According to website Britons are only waiting three years before they start sleeping with someone other than their partner.
They claim the “seven-year itch” is a thing of the past – and modern cheaters move on much quicker.
And it is women who can’t wait for the longest to begin affairs, according to the site.
Of 800 cheaters on the site, the women admitted to waiting only three years and one month before looking for someone else.