Sure, he cheated on her, but the real reason behind the breakup of Ethan Hawke and Uma Thurman's marriage is that it's just plain hard being married to a movie star.
In an interview airing Friday on ABC's 20/20, Hawke discussed the end of his five-year marriage and why he thinks things with Thurman dissolved.
"Uma and I did not split up over anyone's infidelity," Hawke said. "We had a lot of problems before I ever went up to Montreal."
Perhaps it was those problems that led Hawke to begin a relationship with Canadian model Jennifer Perzow.
But how does Hawke explain his betrayal of the woman with whom he has two children?
"It is very difficult for any couple who are married if both people have--are ambitious," Hawke said. "I don't know if it's just too hard to be married to a woman that wants to be a movie star."
Hawke said that both he and Thurman were frequently required to work on location, which put a strain on the relationship.
"You know, you'd come up with these rules," Hawke said. "'One person works, the other person doesn't.' Well, then somebody's always out of town...'Okay, we'll all go away together.' All right, great.
"Then I'm living in a hotel room taking care of my kids while you're off on a film set six hours a day doing what you love. Do that for nine months and see what a good mood you're in," he said.
Since the split, Hawke appears haunted. According to Us Weekly, he's lost 15 pounds since the breakup and suffers from anxiety.
His estranged wife, meanwhile, has been romantically linked with hotelier Andre Balazs, and as the star of the Kill Bill franchise, her career is on the up and up.
Hawke said the pair's celebrity made the split more difficult.
"You know, you hate to have your grandfather read about it...that's what makes you feel ashamed," Hawke said. "It's like, this is our marriage...and now there's all these other voices in the room."
However, he said he doesn't necessarily begrudge his ex her desire for fame.
"I know that she has the right to want that," he said.
Aside from his 20/20 appearance, Hawke has several projects in the works.
His next film is Before Sunset, the sequel to 1995's Before Sunrise, opposite Julie Delpy. He'll also star opposite Angelina Jolie in the action film, Taking Lives. Both films are due out later this year.
Hawke is also participating in a novel scheme to raise funds for the upcoming film Billy Dead by selling preferred shares in the film to interested investors. If the film gets off the ground, Hawke will portray the title character.