Illicit Encounters, which has over 380,000 members UK-wide, surveyed over 600 men and women to compile the list.
The Top Ten was created by analysing the responses of 639 bankers, who were asked the question, "What were the three main reasons you decided to pursue an extra-marital relationship?".
1st To Feel Loved - Bankers have become Public Enemy No. 1 since the credit crunch hit, so are seeking out some overdue affection.
2nd For The Thrill : Professionally, bankers enjoy a good thrill - risk is partof their job. Many said they were simply looking for a real thrill.
3rd Unstable Home Life - Unsociable hours and long journeys into the city meanBankers spend much time away from home; the lifestyle doesn't promote a healthy relationship.
4th To Escape The Mundane - Fantasy and romanticism play a large role in mostpeople's extra-marital relations.
5th To Boost Their Ego - This was a common response amongst male members.
6th To Avoid Costly Divorce - Many members saw an affair as a way of simply avoiding an expensive divorce
7th To Lavish - Bankers want to find someone they can spend all their hard-earned money on.
8th Because They Feel Entitled - Long hours, high stakes and tough decisions make banking one of the most stressful professions out their. Some members see their affair as a reward for their hard work.
9th Because They Can - Opportunity certainly plays a role. Late nights at the office and evenings out drinking provide more chances to cheat.
10th Peer Pressure - Affairs are common in the city, and, especially for male bankers, taking a mistress can be somewhat of a status symbol.