GWYNETH Paltrow and Chris Martin reportedly "butted heads over parenting" their children.
The former couple - who announced last week they were splitting after 10 years of marriage - clashed over their ideas of raising their kids Apple, nine, and Moses, seven.
A source told Us Magazine: "'They butted heads over parenting."
The 'Iron Man 3' star and her Coldplay rocker spouse had successfully managed to juggle their busy careers and family life, but friends believe Gwyneth's "controlling" ways became too much for Chris, 37.
The source explained: "Gwyneth would snipe at Chris and say things to him like, 'You're such a moron'.
"For a long time they balanced each other out, but she was a control freak. Chris couldn't take it anymore."
It was recently reported the pair were keen for a quick divorce and are trying to come to an amicable custodial and financial agreement, as they have no interest in airing their dirty laundry in a trial.
Meanwhile, despite their split, the pair have vowed to stay friends for the sake of their children and are currently enjoying a family vacation.
Another source said: "They're trying to make it as easy as possible for the kids. The whole plan is to do this as amicably as possible."