Ben Affleck, Jen Garner File for Divorce

Jennifer Garner has just filed for divorce from Ben Affleck, TMZ has learned, and it could not be more amicable.

Both Jen and Ben filed pro per -- without a lawyer. Her petition and his response mirror each other completely. The petition and response were filed together, which means it was coordinated.

They both want joint legal and physical custody of their 3 kids. As for spousal support, they left it open, so the judge could award it before the divorce becomes final.

They do not list a date of separation, but in June 2015 they announced their separation.

We've learned there is no prenup, which means all of their earnings during their marriage will be split 50/50, unless they agree otherwise. Ben made a lot more than Jen during the marriage.

There are strong signals the case will not be handled in court, but rather by a mediator, especially by the way the docs were filed. This is the M.O. for disso queen Laura Wasser, who has guided various celebrity couples through mediation and then has them file for divorce pro per.

We're told Ben and Jen are still negotiating a financial settlement. The divorce could become final in 6 months.