Six weeks after Arnold Schwarzenegger revealed they had fathered a child out of wedlock, spouse Maria Shriver filed divorce papers Friday to finish their marriage of 25 years.The former tv journalist & Kennedy relatives heiress cited irreconcilable differences but offered no additional details about the breakup.She also did not list a date when the couple separated, although they announced they had done so on May 9.A week later, the former California governor & one-time action star admitted they fathered a child with a member of his household staff years ago.The filing, which Shriver signed weeks ago, signals an finish to a union that began with a storybook wedding in 1986 in Cape Cod & brought together a weight lifter & rising action star as well as a princess of the Kennedy clan, herself an up-and-coming network newscaster.They apparently entered marriage with no designs that it would finish. Shriver's filing does not indicate the couple had a premarital agreement.That means Schwarzenegger's earnings from a career as a Hollywood megastar, which allowed him to forgo a wage as governor & commute by private jet to Sacramento, likely will be evenly divided along with his estranged spouse.