Elizabeth Petrakis of New York's Long Island recently won a major - and rare - divorce battle after a New York Appellate Court tore up the prenuptial agreement she signed with her husband that hung only on a verbal promise.

Her lawyer, Dennis D'Antonio, called the court's decision "groundbreaking," because in general prenups, especially in New York state, are essentially etched in stone - the fact that the evidence presented was based on an oral promise made the court decision even more "eye opening," he said.

Six weeks before her wedding in 1998, Petrakis, 39, was presented with what her lawyer called a "heavy handed" prenup that would give her $25,000 for every year she was married, but nothing more.

"I put my foot down and said I wasn't signing it," Petrakis told ABC News today.

But four days before tying the knot, she agreed to sign the prenup after her fiancé, 41-year-old Peter Petrakis, promised he would get rid of the prenup once the two began to have children, she told ABC News.

"We were best friends. I loved him and trusted him," she said.

"At first her impression was her husband was procrastinating about tearing it up, so she wasn't alarmed, just attentive to it," said D' Antonio. "She woke up one day realizing she was subjugating her entire life to him, and he could divorce her anytime. That was something that ruined their marriage, going to bed every night knowing this person lied to her."

Elizabeth Petrakis with her new business, helping other people through divorce. (Image Credit: Courtesy of Divorceprepschool.com)

The turning point came when, a few years into the marriage, Petrakis said she realized she was not listed on the title of the dream house the couple had moved into on their wedding night.

"I would rather live in a two-bedroom apartment with someone who loves me than live in a 14,000-square-foot mansion and not trust someone," she said. "I said I was done."

Peter Petrakis, a commercial property developer, is worth an estimated $20 million, Elizabeth Petrakis told ABC News. The home he moved into after splitting from his wife was apparently even more extravagant than the couple's dream house. He described it in the as the New York Times as the "ultimate entertainment pad for a divorced dad."

"He's a good father. He's a very successful businessman. But this prenup was a thorn in our marriage, and he didn't want to give in," said his former wife.

She was often at the home of Dennis D' Antonio, a commercial litigator in Manhattan, to visit his wife, and the two women would discuss the case.

"I was silently critical of the lawyers who were representing her at the time," D' Antonio told ABC News. But as a commercial litigator, he said he did not want to get involved.

But that changed in 2010, when an appellate court struck down seven out of eight legal theories under challenge in the case, except for fraud and inducement, which D'Antonio said would be among the most difficult to prove

Petrakis said that's when she reached rock bottom.

"I was going through an extremely difficult time having to be a mother raising three young kids."

She approached D' Antonio to sit in on a meeting with her lawyer at the time. D'Antonio said he walked into the room expecting to advise her to let the case go.

"But something about the way she was handled got her hooked into me," said D'Antonio. "I felt she got a raw deal, and I didn't think I could win the case, but felt I could fight harder for her," he said.

The trial, which lasted 13 days, was difficult, as D'Antonio said he had to prove, among other points, that Peter Petrakis had no intention of fulfilling his promise to his wife.

But on Feb. 20, Elizabeth Petrakis got the news she had been waiting for: The court ruled that Peter Petrakis had "fraudulently induced" Elizabeth to sign the prenup.

"This is about principle. I thought win or lose, at least I am going to tell my story. I feel like a winner on the inside," she said.

Petrakis now owns her own business, Divorce Prep Experts, which helps others navigate divorce proceedings. She said hundreds of people have attended the company's seminars since its start in 2008.

D' Antonio said the court's decision was something others in a similar situation could learn from.

"If you are too greedy and marginalize a spouse, it's a lot easier for an Appellate Court to agree with a legal argument that would invalidate a prenup than it otherwise might be if that prenup was fair. It's not a given that the prenup is going to rule at the end of the day. It levels the playing field with couples dissolving a marriage with a prenup."

Calls to Peter Petrakis and his lawyers by ABC News were not immediately returned.