Page Six says that ABC Elizabeth Vargas’ husband, Marc Cohn, had an affair with Flywheel co-founder Ruth Zukerman while the ABC anchor was in rehab.

The Tabloid writes that their sources claim that songwriter Cohn — who wrote “Walking in Memphis” and has been married to Vargas since 2002 — was seen with the divorced spin guru during and after Vargas was undergoing treatment for alcohol addiction.

Vargas sought treatment in rehab last fall and returned to the air on “20/20” in January. Prior to that, Vargas and Cohn were both friends with Zukerman after becoming regulars at her Flywheel spin classes.

One source told us, “Marc made out he was an angel, standing by his wife while she was in rehab. But meanwhile, he started an affair with a mutual friend, Ruth Zukerman.”

The source said the affair came to light when they dined together at a restaurant near Flywheel’s Flatiron studio, just after Vargas left rehab. “A mutual friend spotted Ruth with Marc and called Elizabeth,” the insider said. A second source added, “It was disgusting that he was with Ruth while Elizabeth was in rehab.”

Vargas, who has two sons with Cohn, ages 7 and 10, was not available for comment. An ABC rep declined to comment.