Whitney Duncan, Survivor Star: Dating Keith Tollefson, Secretly Married to Donny Fallgatter?

Whitney Duncan’s Survivor bio says the country music singer is 27, lives in Nashville, and is an outgoing, happy, honest. It’s the honest part being questioned.

The blonde, who portrays herself as single on the show, has in fact been married since August 1, 2010, to Donny Fallgatter, 32. They wed in Gatlinburg, Tenn.

She was also runner-up for Country Weekly‘s “Hottest Bachelorette” this year.

The reason this is significant? Because Whitney Duncan has been part of a relationship with Survivor co-star Keith Tollefson (pictured) playing out on TV.

Fallgatter, from Bismark, N.D., is lead singer for the band KingBilly. Their paths crossed in June 2010 and their romance heated up quickly after that.

Whitney Duncan soon moved in with Fallgatter. Before she left to compete on Survivor in May, the couple announced their engagement to family and friends.

“Donny was totally faithful while she was gone,” says a close friend. “He even went to help out at her parents’ house in West Tennessee a couple times.”

As for Whitney’s faithfulness …

At one point before returning home, Duncan phoned Fallgatter, and, as Fallgatter told the friend, “He said she sounded weird, like something was up.”

Fallgatter’s suspicions were confirmed in a subsequent call, the friend says, when she confessed that she was in a relationship with Keith Tollefson.

“Donny sent me a text that said, ‘Whitney got into a Survivor relationship.’ I called him and he was upset so I went over to his place,” says the friend.

“That’s when he told me that she wasn’t his fiancé, but his wife, that they had gotten married the summer before. I was totally shocked.”

On Aug. 20, Duncan Tweeted, “Moving furniture all day … sweeet. I’m gonna be happy when I get a home one day and never have to move again.”

Since then, she and Tollefson have been spotted around Nashville, and she refers to a BF in her Twitter posts. Tollefson, 26, was voted off Survivor Nov. 2, leaving Duncan to fend for herself. A rep for Duncan had no comment.