Ryan Phillippe thinks age is the reason why his marriage to Reese Witherspoon didn't work out. The 40 year old opened up on "Larry King Now" about when he knew it was over.

"I think more of the problem was age. When we got together we were so young," Phillippe told Larry King. The former couple met on Witherspoon's 21st birthday. Phillippe was 22.

"I think it can create issues with two people in this industry because there's so much noise that goes along with it."

PHOTOS: Friendliest celebrity exes

The "Secrets and Lies" actor, who has two children with his ex-wife, said the two are still "very much" friends.

More On This...

Witherspoon and Phillippe split in 2007 after rumors swirled he had an affair with Australian actress Abby Kornish. They were married for eight years.

"I'm a pretty regular dude," he said of being labeled a "bad boy." "I'm also a pretty dedicated dad and have multiple companies, so there's not a lot of time for me to be a Hollywood bad boy."

Phillippe also has a daughter, Kailani, 3, with "Pitch Perfect 2" actress Alexis Knapp. He is currently dating civil rights lawyer Paulina Slagter.