Researchers found that millions of men keep an account they opened years ago to correspond with an ex-partner or somebody their other half doesn't like.
Others said they deliberately set up the account because they were having an affair, while keeping financial issues from their partner also emerged as a common reason, the Daily Mail reported.
One in twenty men admitted buying a second mobile phone to ensure ultimate secrecy and 77 per cent of men said they regularly deleted text messages in case their wife or girlfriend went 'snooping' through their phone, found the survey by a UK-based software company.
"Of course there are legitimate security concerns that might involve someone setting up a second email address, or clearing browser history," Mike Hodges, COO at BullGuard, who carried out the research, said.
"We would hope that in most cases this is being done for moral reasons for example to help avoid phishing scams and not because people are being unfaithful or up to no good," Hodges said.
The poll also found 20 per cent of men who keep emails hush-hush said there were certain aspects of their life their spouse just didn't need to know about.
One quarter of men said they would be left red faced if someone went through their 'Google' history.
It also emerged that more than one in twenty men has even been dumped because of something incriminating a partner had found on their phone or PC.
A crafty one in four men use a plethora of different passwords to their email accounts and social networking sites to try and deceive the lady in their life.
Nearly a quarter said they had content in their inbox that they wouldn't want their partner to see, with confirmation of purchases they have bought being the main reason.
Although a third said they had flirty emails stored that they need to keep under wraps.
One in ten men has confided over email to friends about their relationship problems which could also land them in hot water with their wife or girlfriend.
Of those polled, two thirds of all men choose not to share their passwords with their other half and 23 per cent admitted to being secretive about what was stored on their phone and PC.
A guilt ridden 18 per cent of men also feel the need to delete certain pictures and video clips 'just in case'.
