In a Facebook post, his mother Nicola Urquhart, a policewoman, confirmed he had an account with Fab Swingers.
Last week she said during an online Q&A session that her son was a ‘social hand grenade’.
On Monday it was revealed police were bringing in specially trained dogs to search central Bury St Edmunds.
A police spokesman said: ‘Police are aware of the social media and websites Corrie was using and this is part of our investigation.
He was last seen on CCTV in the town centre at 3.25am, wearing a light pink Ralph Lauren shirt, white jeans and brown suede Timberland boots with light soles.
Images show him walking from a shop doorway and into a horseshoe-shaped area in Brentgovel Street.
He had previously dated an actress called Chloe Fox, though their relationship ended in 2015.
It was not clear last night if the page was genuine.
Five months ago, Mr Mc Keague also opened a joint account on the partner-swapping club with his 21-year-old girlfriend April Oliver – who is expecting their child later this year.
It said ‘we are a young couple, but we know what we want.’ Missing RAF airman Corrie Mc Keague (left) trawled the internet for casual sex and opened a joint account on the partner-swapping club with his 21-year-old girlfriend April Oliver with a scantily clad woman used as the profile picture (right)Detectives last night said they are examining the airman’s links to the website and other internet activity as part of their inquiries.
She said the airman did not know about the pregnancy before he vanished.
Mr Mc Keague, a gunner and team medic based at RAF Honington in Suffolk, disappeared after becoming separated from friends while on a night out in Bury St Edmunds.