"After much thought and careful consideration, we have made the difficult decision to divorce," the couple said in their statement to ET. "We go forward with love and friendship for one another and a commitment to co-parenting our children whose privacy we ask to be respected during this difficult time. This will be our only comment on this private, family matter. Thank you for understanding."
A source tells ET that despite recent speculation that Affleck's workaholic ways are to blame, Garner is at least as busy as he is. "Both Ben and Jen are working all the time," the source said, adding that no formal paperwork has actually been filed yet.
And even if the timing seems significant, the source adds, "There's no relevance to their 10-year anniversary having been yesterday."
Another source close to the situation tells ET the split is amicable, and that the two have been in therapy for close to two years trying to make things work. The source adds that they are believed to be working with a mediator on the terms of the divorce.
Affleck, 42, and Garner, 43, share three children: Violet, 9, Seraphina, 6, and Samuel, 3.
The couple met as costars on the set of their 2003 film Daredevil and started dating soon afterward. At the time, Garner was married to her Felicity co-star Scott Foley -- the two filed for divorce in May 2003 -- and Affleck was engaged to Jennifer Lopez.