Mark Wood has already claimed she "went like an express train" during one sex romp in the toilets of a train from London to Glasgow reports the Daily Star.
The 32-year-old is to reveal even more about their relationship in his first TV interview.
Posh, 30, insisted in her own documentary that Mark's tale of their high-speed romp was a lie. Now the burglar alarm engineer will get his revenge by revealing his side of the story in Victoria Beckham's Secrets, to be screened on Five.
Mark, from Hertford, split with Posh shortly before she began seeing David Beckham in 1997.
He was furious when she mocked him in ITV1's Being Victoria two years ago. Posh said: "For some bizarre reason we got engaged. He was an alarm engineers. If only he's stayed in that cupboard that I met him in at my mum's house."
A Five source said: "Mark has never spoken before in public about his relationship with Victoria but feels it is time to set the record straight."
Posh, now pregnant with her third child, has not taken part in Five's documentary, which will be screened later this month.
