Los Angeles ? No mother-in-law sleepovers. Only one football game per Sunday. Mandatory sexual positions. With celebrity marriages often shorter than Jessica Simpson’s Daisy Dukes, the power of the prenuptial agreement cannot be denied.

Simpson and soon-to-be-ex-husband Nick Lachey didn’t have a prenup – he actually had more earning power than she did when they got married three years ago – so Simpson could have to part with half of the $30 million she earned last year. That’s a lot of Chicken of the Sea.

Other recent breakups include Valerie Bertinelli and Eddie Van Halen, and Christina Applegate and Jonathon Schaech. Prenups are the norm for most stars – even regular folks should have one, if you listen to Kanye West – and these documents can dictate far more than who gets what. Attorneys say some recent celebrity prenups include:

¢ Limiting the wife’s weight to 120 pounds or she must relinquish $100,000 of her separate property.

Jessica Simpson, left, and her husband, Nick Lachey

¢ Allowing a spouse to perform random drug tests, with financial penalties for positive results.

¢ Requiring a husband to pay $10,000 each time he is rude to his wife’s parents.

¢ The previously mentioned rules regarding mothers-in-law, football and sex.

“Everything is legal unless you’re dealing with custody of children or child support,” said Los Angeles divorce attorney Robert Nachshin, who has represented Barry Bonds (his ex signed the prenup the day before their wedding) and author Terry McMillan (who discovered the young hubby who brought her groove back was gay). “Everything else is up for grabs.”

Infidelity clauses are common, Nachshin said. Michael Douglas agreed to pay Catherine Zeta-Jones millions should he stray, and Denise Richards made similar requirements of Charlie Sheen. Britney Spears was reportedly so taken with Kevin Federline that she refused to sign a prenup until her mom and business managers intervened.

“They may be blinded by love and lust,” Bennett said, “but they still need to be protected.”