When I was pregnant with my second child, I told my husband that our oldest would always be my favorite. “You can have No. 2,” I said. “I get Nate.”

Then baby Harvey came and shook up our little world. When everything settled back into place, it turned out that I didn’t have a favorite. I loved the baby with all the purity and joy he exuded from his fat little self. And I loved Nate deeply and intensely, my wrenching feeling mirroring his thrilling, emotional personality.

What I didn’t count on was that Nate would choose a favorite parent, and it wouldn’t be me.

“Give me a kiss goodbye,” I said to 4-year-old Nate the other evening as I left to go to a meeting.

“I don’t have time; I have to help Daddy!” he said, rushing into the kitchen where his father was making pancakes for dinner. Another time, Aaron put on his coat to go outside and check whether ice had formed on our front path (we recently moved to a cold climate). Nate had a suggestion:

“Mommy should do it,” he told his father, “because I don’t want you to slip.”

Every day, I pick up Nate from preschool, and we spend the afternoon together. But the highlight of Nate’s day is at 6 p.m., when his father gets home from work. By that point, he’s usually been asking when Daddy will be home for several hours.

Once Aaron walks through the door and Nate rushes into his arms, I am irrelevant to the evening’s affairs. Aaron barely has time to kiss me hello before he is dragged off to build Lego airplanes and spin elaborate fantasies where he and Nate are members of a squirrel family. Aaron is the daddy squirrel, Nate is the kid squirrel and when he’s awake, Harvey is the baby squirrel. If I’m lucky, I’m cast as the homeowner who feeds the squirrels. When I’m not lucky, they aren’t squirrels at all, but a family of bees who are trying to sting me.

“How about I’m the queen bee?” I propose.

“No,” Nate says.

I can remember a time when Nate cried when I went out for an evening, when he wanted me to hold him all the time and sit in his room until he fell asleep. As he got older, he began to look to Aaron for fun and play, but he still wanted me to comfort him when he was upset or hurt.

In the months after Harvey was born, Aaron spent more time with Nate, getting him ready for school in the morning and taking him out on adventures on the weekends while I was consumed with breastfeeding the baby around the clock. But even after the chaos of the newborn period abated (Harvey will turn 1 in March) and everyone started getting a lot more sleep, Nate stayed glued to Aaron.

Nate loves his brother and never acts jealous of him. But Harvey’s birth changed our family, and one major change is that Nate now looks to his father as his primary parent, for both fun and for emotional support.

Aaron and Nate have a beautiful relationship, and I feel lucky to be a witness to it. They make books together, talk endlessly about animals and even sometimes dress alike, at Nate’s request. Nate and I have special things that we do together, like baking cookies and making Danish ebelskiver pancakes on Sunday mornings. We read books and roughhouse when his brother is taking a nap. But when he has the option, he almost always chooses to spend time with his dad, not with me.

I don’t believe parents should be needy for their children’s affections, and I know that childhood is characterized by phases; our family dynamic will always be evolving and changing. Still, I can’t say that Nate’s rejection doesn’t hurt. He made me a mother, and I learned that aching, longing love from him.

If Nate sometimes places me on the sidelines, I am the star of the show as far as the newest member of our family is concerned. Baby Harvey demands my constant attention; great consternation ensues if I enter a room and don’t pick him up right away. Hanging out with his dad and his brother is all fun and good, but he makes it clear that mom’s the one who should be feeding him, dressing him, putting him to bed and comforting him when he cries. And I’m eating it up: every giggle and every time he falls asleep in my arms.

Right now I’m Harvey’s sun; his world revolves around me. It’s all the more precious and bittersweet because I’ve seen how a child can leave your orbit.