Simone Callahan, who reunited last December with the spin bowler known also for his womanising, told a woman's magazine she caught Warne cheating on her while he was in London.
As Callahan got the couple's three children ready for school in Melbourne, a text dropped into the inbox of her mobile phone, she told New Idea magazine.
"Hey beautiful, I'm just talking to my kids, the back door's open," the message from Warne said.
"You loser, you sent the message to the wrong person," Callahan sent back.
She told the magazine the message confirmed her suspicions that Warne was again cheating on her and that his lover had been to their London home before.
"He confirmed there was someone else and told me he was sorry. I gave it to him big time -- I left him in no doubt as to what I think of him and that was it."
Nicknamed "Hollywood", the 38-year-old Warne was rarely out of the limelight as a player and also had to endure seemingly endless tabloid headlines for boisterous post-match celebrations, phone sex and drug scandals.
He and Callahan divorced in 2005, with Warne later saying his womanising was something he did to ease the loneliness of long cricket tours.
Warne took a world record 708 wickets in 145 Tests and currently captains English county side Hampshire.
