Reese Witherspoon may pay dearly for her split from husband Ryan Phillippe as the couple allegedly have no prenuptial agreement. The actress now earns $20 million a movie while her husband only commands $2.5 million, but under California law earnings during a marriage are split 50/50 if no prenup is in place. In 2005 alone Reese earned $30 million dollars for her two films 'Just Like Heaven' and her Oscar-winning role in Johnny Cash biopic 'Walk The Line',while Ryan has only appeared in two hit films in the last six years -'Gosford Park' and 'Crash'. However, sources say the couple are keeping the split amicable and will continue to do so for the sake of their two children, seven-year-old daughter Ava and three-year-old son Deacon. A source told gossip website "On a scale of one to ten, one being peaceful and ten being war, Ryan and Reese's split is a three."But Ryan's mother Susan Phillippe said: "We're a little bit devastated and heartbroken. "The source also claims there is no chance of a reconciliation, and it is only a matter of time before divorce papers are filed. Reese, 30, has allegedly contacted celebrity divorce lawyer Robert Kaufman,who has represented Jennifer Aniston and Lisa Marie Presley, to assist inher in the split. It was alleged the other day that the cause for the break-up was 32-year-old Ryan's affair with Australian actress Abbie Cornish. The 'Cruel Intentions' actor is said to have fallen for his 24-year-old co-star on the set of 'Stop Loss' where it was reported that the couple were extremely open about the relationship that developed between them during filming.A source said: "Ryan did not go out of his way to hide the fact that he was having a fling with his co-star."A representative for Abbie has denied allegations of any affair while representatives for both Reese and Ryan refused to comment.