The former Here Comes Honey Boo Boo matriarch, 35, bursts into tears as longtime love Mike "Sugar Bear" Thompson makes a devastating confession in RadarOnline.com's exclusive preview from this week's episode of the WE tv series.
"You know how you say I have cheated? I have," Thompson tells his common-law wife of more than ten years, as cast members watch in awe.
"And I'm here now to change that. But that is the only one I've actually cheated with. The rest of them I just talked to on the phone."
Though the 43-year-old father of former pageant queen Alana "Honey Boo Boo" Thompson, 10, swears he's come completely clean, Shannon remains skeptical through the tears.
"I want to make sure that it's only been one, because I think it's been more than one," she says.
"It's been one I swear to God!"
Shannon tells the cameras that she knows when her soft-spoken man is lying.
"When he gets defensive…there's something he's hiding," she insists. "That's the way he gets at home."
The affectionate pair, who often boasted about their wild sex life on their former TLC reality show, split in September 2014 amid rumors Thompson cheated with women he met online.
In a previous episode of Marriage Boot Camp: Reality Stars, Shannon confessed that the couple never actually had sex toward the end of their relationship.
Soon after the breakup announcement last year, Shannon was spotted hanging out with an ex-boyfriend who was convicted of molesting her oldest daughter, Anna Cardwell, 22, as a young girl.
The rendezvous set off a huge scandal that ultimately led to the cancellation of their TV show. (Shannon denies ever rekindling the romance with her felon ex.)
Will Sugar Bear and Mama June make it work? Watch the clip above, and don't miss the next episode of Marriage Boot Camp: Reality Stars on WE tv this Friday at 9 pm est.