The Grey's Anatomy star, 27, and her actor husband, 30, became third-time parents on May 7, when Anniston Kae joined Noah, 5, and Taelyn, 2.
Chyler: We planned on having two children. Anni was a big surprise!
Nathan: She's a happy, easygoing baby. She sleeps through the night.
Chyler: Going from zero to one was a shock. One to two was more challenging. But once you're used to multiples, you learn how to organize. You get more confident—with No. 3, it's like, calm mom, calm baby.
Nathan: There's so much love in these kids. When Anni came, Noah took on the role of the older kid.
Chyler: He's protective. If Taelyn wants to play with the baby, he says, "Be gentle."
Nathan: Taelyn had to find her way. She was a baby, then a new baby came, and she was like, "Who am I?" Once she got her princess dress, she decided, "That's who I am!" She wears it everywhere.
Chyler: We've had to upgrade everything—the car, the house. Everything gets bigger. We had to get a double stroller, we carry a lot more stuff, and have a lot more laundry.
Nathan: Anni completed our family. I can't imagine it without her.