From PageSix

November 1, 2006 -- RYAN Phillippe's cruel intentions to cheat on wife Reese Witherspoon brought an end to their glam Hollywood marriage, Us magazine reports.

The "Flags of Our Fathers" star couldn't resist his seven-year itch when he brazenly played around in public with 24-year-old Aussie actress Abbie Cornish.

"Ryan admitted it was true and said, 'We need to just end this.' Reese literally had no choice," an anonymous source told Us.

Reps for Phillippe, 32, and Oscar winner Witherspoon, 30, announced Monday they're splitting up after seven years of matrimony. Their reps could not be reached for comment last night.

Phillippe and Cornish allegedly grew close in Austin, Texas, on and off the set of their indie flick, "Stop Loss." Other sources have pointed to a different castmate.

"We're a little bit devastated and heartbroken," mom Susan Phillippe said.

The National Enquirer says the final straw came two weeks ago, hours after the New York premiere of "Flags," when Witherspoon found incriminating e-mails on her hubby's BlackBerry.

A bunch of internet posters are saying they didn't see this coming and they were a "perfect family". Meh.

I KNEW something was fishy when Reese won the Oscar for Walk The Line. Her speech was good but she gushed over Joaquin for 5 minutes and mentioned Ryan but almost as if she HAD to. After that I kept my eye on her.

She was at an outdoor party with Selma Blair and Selma had her hand on Reese's handso I couldn't tell if she was wearing her ring. I don't think so but not sure. I kept looking after that.

Lainey is saying they may have had an "agreement" that he could go elsewhere as long as she didn't have to hear about it and that her & Joaquin may have hooked up during filming. I hope not. Evidently Ryan wanted out so that's why he got with an actress and let it all out and forced Reese's hand. AND there is NO pre-nup!!! hee hee