"I worked with WWE on and off from 2006-2010 and can back up most everything you say about Cena and his cheating ways man!" he tweeted to Doane on Wednesday.
Doane, who labored as Kenny of the Spirit Squad and Kenny Dykstra for WWE from 2006 to 2008, blames an affair between Cena and Mickie James for ruining his relationship with the former Diva and ultimately costing him his job.
In response to a fan tweet that Cena's a good hearted person, Katera wrote, "Cheating multiple times with different women while on the road when his wife was at home unaware ... not cool!"
Katera says Cena would often discuss his sexual escapades with Jonathan Coachman, who worked for the organization as an announcer through 2008.
"Constant talking about hooking up with this chick or that chick," Katera says of Cena. "Him and Jonathan Coachman were always talking about it!"
Cena's estranged wife Elizabeth Huberdeau is convinced the WWE Superstar was unfaithful during their marriage and is now on a mission to prove it in court. Her attorney Raymond Rafool told TMZ.com last week they've been receiving tips of Cena's extramarital affairs which, if proven true, could affect their prenuptial agreement and the terms of their pending divorce.