The 42-year-old star, who announced he is divorcing the actress after 10 years of marriage in a joint statement on Tuesday, battled to try to save their relationship for the sake of their three children, Violet, nine, Seraphina, six, and Samuel, three.
"He's devastated. Nobody intends to go down this path. They both battled, and he really battled to try and save the marriage but ultimately it was the best thing for the kids and for him and Jen.
"These are two people who really tried to save their marriage and worked really hard at it. Ultimately they had grown apart and they did what was best for their kids," a source close to the 'Gone Girl' star told people.com.
The Oscar winner, who has been staying in hotels for the past few months, is now building a separate bachelor pad on the grounds of their Pacific Palisades home in California so he can continue to be a hands-on father, and the duo have hired a mediator to help them divide their vast fortune.
The insider added: "These are things that they have consciously done because they want to make sure that this is as easy as they can make it on the kids."