Allegations of divorce controversy for 'Da Vinci Code' author

"Da Vinci Code" author Dan Brown is facing a real-life plot twist that reads like his bestselling thrillers.

Brown's private divorce details went public after his ex-wife accused him of leading a double life.

The bestselling author has penned imaginative tales of intrigue and deceit, but his ex-wife of 21 years Blythe Brown filed a lawsuit Monday that claims he was living a "secret double life."

ABC News obtained a copy of the lawsuit filed in New Hampshire, which claimed Brown removed "substantial funds from their hard-earned marital assets to conduct sordid extra-marital affairs with women -- one half his age." The lawsuit also stated that Brown bought "a prizewinning stallion horse worth $345,000" for one of the women.

Family law attorney, who is not involved in the case, Laura Wesser, told ABC News that Blythe would need to prove how their money was spent.

"If she could show that the money used to purchase the horse came from their joint funds, she might be able to show that she "was entitled to all or some of those funds," Wesser explained.

The suit also claimed that the 56-year-old author misrepresented the couple's wealth in a sworn financial affidavit in their divorce agreement and hid multiple future projects worth "millions" from Blythe. Those included a TV series based on writing she said the couple "created together" and a children's book due out in September.

In a statement to ABC News Blythe said "the lawsuit is about standing up for myself."

"We worked so hard together, struggling to build something -- After so much pain, it is time for truth," she said.

Brown has adamantly denied all allegations and called them "fictional and vindictive," he told ABC News.

"Any suggestion that I was not completely honest in financial disclosures during our divorce is wrong," he continued, adding that his ex-wife received "more than half" of the couple's assets.

"The fact that he had relationships with other people in the marriage -- is not something he can be penalized for as part of the divorce," Wesser said. "if he really didn't say these are things that are generating income for me, then that could be a problem for him."