Clean-up teams allegedly found the duo as they cleared the controversial Flamefest site after the three-day event over the weekend near Royal Tunbridge Wells in Kent.
The man was pronounced dead and the woman was taken away in a helicopter. This afternoon, a man in his 20s was arrested on suspicion of possession of class A drugs.
It was also revealed tonight that the woman was out of intensive care in hospital.
The festival caused uproar in the exclusive town after it was announced, offering an 'adult play area' staffed by dominatrix and a variety of kinky workshops. Police will be searching a number of addresses in relation to the investigation, but said they do not expect to make any more arrests.
Only yesterday organiser Helen Smedley praised everyone involved including stewards and 'dungeon monitors' for helping to run the 'brilliant' event.
Miss Smedley had previously said members of the public would not witness 'outdoor sex' as revellers would go to 'safe places' to romp at the 'private event'.
Around 250 people paid up to £600 to attend the weekend-long festival - which finished on Sunday - and organisers drafted in extra security to stop gatecrashers.
But South East Coast Ambulance Service were called to reports of two people found unconscious at a field in the Southborough area of the town at 6am today.
Witnesses reported seeing five police cars and two ambulances today at the site.
Police were pictured focusing the investigation close to a white bell tent among other bell tents on the site. An area outside one of the tents was taped off. One neighbour, who wished to remain anonymous, said he was woken by the sound of the air ambulance landing at around 6am today.
He said: 'We heard at about 6am this morning the helicopter flying over. We heard at the beginning it was two ladies who had died of carbon monoxide poisoning.
'We've since been told it was a man in his 50s and a young woman. We don't know for sure. It's so sad.
'Maybe they were cold and put a stove in their tent or something? That's all we know. The police have been there all morning.'
A black private ambulance drove out of the campsite today carrying the body of the man. A post mortem will now be held to establish the exact cause of death.
Zulhash Uddin, ward councillor for High Brooms and Tunbridge Wells at the local council, has called for a full review of safety measures at future events.
He said: 'It is so sad to hear that somebody has lost their life. My heart goes out to the family affected.
'More importantly safety is a number one issue at events like these and this will trigger a review when we do get the council issuing permits and licensing.
'Obviously local people did raise concerns about the festival. I am sure this will be looked at by the appropriate agencies.
'As a local representative obviously I will be speaking to the relevant agencies to make sure if there's anything we can learn to make sure it never happens again.
'This is very tragic. Obviously for now we need to be patient and find out the exact cause of this incident.'