"Big Brother" contestant Jason Dent was way out of bounds when he joked about raping the wife of houseguest Kevin Schlehuber ... this according to Kevin's wife, who's deeply disturbed by Jason's remarks.
Kevin's wife, Deborah, tells TMZ ... Jason making those comments on the show's live feed, while laughing hysterically, is the worst thing she's ever seen. She says while her husband signed up for 'BB' and all that comes with it ... she and her kids didn't.
Deborah also calls BS on Jason's family's apology and claim that the jokes were taken out of context -- because it would never cross her husband's mind to say something so horrible.
Kevin and Deborah have 7 children together -- 6 of them girls -- and she works as a neonatal nurse in Boston. She says they're a nice, hardworking family and she's appalled her husband's season of "Big Brother" has turned so ugly ... mostly due to Jason.