We don't blame her!

Jennifer Garner has handled her split from Ben Affleck like a total champ, but she's not about to be cool with his mistress-turned-girlfriend Lindsay Shookus playing stepmom to her kids.

"Jen doesn’t want the kids around Lindsay or having her in their lives. She has many reasons,” a source dished to Us Weekly, adding "the fact that Ben had an affair with her" is a main sticking point.

"Ben understands and has honored her request. They’re good friends. She wants him to be honest and he usually is. She tends to find out about things, and Ben is very open with her. They both want what’s best for the kids and have made a commitment to see that through," the source added.

The Love, Simon star isn't willing to negotiate when it comes to the Oscar winner's sobriety, either.

"The one thing she’s not flexible on is sobriety. Jen is hesitant to sign off until she’s certain that the kids will be in the best hands at all time. Finalizing the divorce has been a long process because of it," the insider revealed.

Somebody give Jen G an award!