Mandy says she recently had her biggest fear confirmed: her husband, Eric, has been having an affair with an 18-year-old.

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“My husband’s affair with Brooklyn is ruining our marriage,” Mandy says. “Everything that Eric tells me is a lie.”
 
Mandy says when she first met Brooklyn, she thought she was a “sweet, young” girl, and she even let her stay in their home. Then, she says, she learned she was a runaway. Mandy says when she found out Eric and Brooklyn were spending time together, she called the police and had her husband arrested.

WATCH: Teen Says Relationship With Married Boyfriend Is ‘Perfect, Definitely Fantastic’

“Eric is Brooklyn’s sugar daddy, but he also wants to maintain his family as well,” Mandy says. “I’m at the end of my rope with Eric lying and cheating.”
 
In the video above from Monday’s episode of Dr. Phil, see what happens when Mandy comes face to face with Brooklyn on Dr. Phil’s stage.
 
Is her marriage worth fighting for? Hear what Dr. Phil says on Monday. Check here to see where you can watch.