Her comments came after the TV channel confirmed last week that Rory Alec would be stepping aside as chairman and chief executive with immediate effect following an undisclosed "moral failure".
In a lengthy statement broadcast live on GOD TV, Wendy said Rory had been having an affair and that he is currently staying on the farm belonging to the woman's father in South Africa.
She also stated that he no longer wishes to be involved in the GOD TV ministry, which they founded together in 1995.
She described Rory's decision as a "satanic assault on God TV and Rory and I".
She said he had met the woman in Austria as a result of working with her on her jazz album. She described the woman as a musician and jazz singer who had asked Rory, himself a musician, to help her with her album. "You get in a music studio, it is one of the most seductive environments you can have," she said. "The princes of hell designed a perfect strategy to hook his soul in through that seductive Jezebel spirit."
Rory and Wendy Alec. Photo: God TV
"After 20 years of service, I have had a moral failure this year," Rory said. "For this reason, I am stepping down. Please forgive me for the disappointment I've caused, but I know your eyes are on Jesus who is the author and finisher of your faith and not on me, an imperfect man. It is with a heavy heart that I confirm my season with GOD TV is over for now."
It claims to have an audience of more than 900 million people, and broadcasts a mixture of sermons and uplifting stories of people saved by faith.
According to a report in RawStory, Rory will be replaced by Benny Hinn, a popular televangelist who divorced his own wife in 2010 after he allegedly had an affair with fellow televangelist Paula White.