How to Break a Prenup

July 9, 2008— -- Cynthia Rodriguez believes her marriage to Yankee slugger Alex Rodriguez is "irretrievably broken." She wants their two kids, their $12 million Florida mansion and her Mercedes.

She also wants a "determination as to the validity or enforceability" of the prenuptial agreement they signed before getting married.

Just because Cynthia signed a prenup does not mean a judge won't throw it out, divorce attorneys told ABC News. Airtight prenuptial agreements are rare, and a number of factors can give an angry spouse the means to get out of it.

Rules for prenups vary from state to state, and each contract has to be evaluated on its individual merits. But lawyers looking to help clients get out of prenups generally look to see which of the rules may have been broken when the contract was signed.

"Any lawyer looking to get his client out of a prenup is going to ask three questions," said James Hennenhoefer, president of the American Academy of Matrimonial Lawyers. "When was it signed? Where was it signed? And under what conditions was it signed?"

Timing is a big deal when it comes to breaking a prenup, lawyers said. The closer the contract is signed to the wedding date, the easier it is to break -- a result of parties not having had time to fully vet the contents of the contract.

"The first thing I'll ask a client looking to sign a prenup is whether a wedding date has been set," said Mark Seff, a family law attorney in Hollywood, Fla. "If they're looking to sign an agreement at the last minute, a few days beforehand, I turn them away."

The Rodriguezes were married in November 2002, one month after signing their agreement.

Another question of time has to do with how long the couple was established before they decided to get married.

"If the couple had been living together, was already involved sexually and had perhaps made babies together, their relationship is unique," Hennenhoefer said. "If the prenup does not reflect that, it can be tossed out. If the couple was established, they have a confidential relationship, which is different from the sort of fiduciary relationship two people looking to enter a business contract might have."

Aside from the timing of the agreement, a lawyer is also going to look at what other "external factors" were at play when the contract was signed, said New York divorce attorney Raoul Felder.

"Getting out of a prenup isn't a do-it-yourself job," Felder said. "You need a lawyer to look at the external factors and determine if there was extortion, fraud or duress

Those are all legal ways of saying that if you were tricked or forced into signing the agreement, you can likely get out of it.

Another way out of a contract is to prove you were "lacking capacity," Felder said.

"If someone said, 'Sign, or I'm going to hit you over the head,' that's duress," he said. "If you were taking drugs when you signed, that's lacking capacity."

Seff, the Florida attorney, said that not having a lawyer review the contract might also be grounds to toss the agreement.

"Typically, a wife who is marrying a wealthier husband goes along and signs off on it," he said. "A lawyer reviewing the contract during a divorce is going to check if that party had the benefit of counsel."

In 1989, it was widely reported that a judge ordered director Steven Spielberg to pay his first wife, Amy Irving, $100 million in a divorce settlement after throwing out a prenuptial agreement written on a bar napkin and signed with no lawyers present.

Many lawyers are increasingly videotaping the signing of prenups, to prove at a later date that both people willingly entered the contract "without being influenced or coerced," Seff said.

According to Felder, infidelity alone isn't grounds to throw out a prenup.

"Cheating isn't a deal breaker," he said. "Everybody does that all the time."