Never was I so fortunate to have a calm, rational husband beside me, than when my son Luke’s Upper East Side school told us they would not be admitting his younger sister.

I had always assumed my daughter, Meg, would be just like my boy, who was smart and funny, athletic and popular. He fit in wherever he went. I was realistic enough to figure they’d have their own interests, but assumed they would fundamentally live the same life.

“She would not do well here,” said the principal, explaining that Meg, in their big classes, would not get the one-to-one attention she needed, pointing out how their traditional learning style would not do right by a child who “learns differently.”

Intellectually, I understood, but emotionally I couldn’t accept that my family was being divided. I looked to my husband, Neil, to pick up my slack and fight for our daughter’s rightful place. To my horror he sat listening intently, nodding.

Seeing our opportunity to persuade the principal slipping away, I began begging—offering to hire tutors, even announcing that I would foot the bill to put an assistant teacher in the classroom. Where I would get the money I wasn’t sure, but my mouth just kept running.

As I made my pleas, I felt the warmth of a familiar hand on mine. Neil’s touch however, was not one that said, “I’ve got your back,” but, “Sit back and be quiet.”

The next thing I knew, we had said our good-byes, I had my coat on, and we were standing out in front of the building. We walked the half a block to the corner, in which time I ranted so loudly my voice echoed on the otherwise quiet block, I mentally enrolled both my children in a different school, and the word “sue” left my lips several times.

A cab pulled up and before getting in to go to work, Neil broke his silence to tell me that Luke should stay put and that Meg should attend a school where she is wanted. Then he kissed me and went on his way.

That night, Neil asked if I had investigated possible alternatives for Meg. I told him how I’d spent the day trying to get through to a contact high up on the educational food chain who would surely be able to change the principal’s mind.

With a chest-heaving sigh, he slipped his hands into the pockets of his navy blue, Brooks Brothers trousers and like a stately Abraham Lincoln, this man, who is the oldest of seven, began his lecture: “People are different, even if they grow up in the same house,” he said. “Everyone has to get where they’re going in their own way and time.”

I am an only child and was not exposed to the daily anthropological study on human behavior that was his household. I didn’t want Meg to be different. I wanted her swathed in a blue blazer with a crest on the pocket. Plus, I couldn’t help but think that word would spread along the gossipy mommy grapevine about my failure to procure a place for my child.

“Who cares what people think?” asked my husband.

In the end, it took less time than I thought to find a beautiful school that welcomed my girl. You’d think I would have been grateful, yet after dropping her off the first day, the way I carried on rivaled Meryl Streep’s performance in “Sophie’s Choice” when she handed her daughter over to the Nazis.

That year, I harassed my son’s principal with meeting after meeting to share the progress my child was making at “that other place,” hoping to turn the educator’s “no” into a “yes.”

After a while, my relentlessness lost its charm. Neil put a moratorium on even discussing my ideas. He instead encouraged Meg to do her best and enjoy where she was.

She took her father’s advice, and not long after, stopped asking when she’d be able to join her brother.

I was finally able to put to rest the saga of the school that might have been, when last June my son graduated. Only then could I appreciate that, while I was looking over my shoulder at what I couldn’t have, Meg had found her groove where she was enrolled. As my husband had predicted, she was getting where she needed to be. A bit more slowly, so is her mother.

Lorraine Duffy Merkl is a columnist for Our Town and the West Side Spirit and the author of the novel, “Fat Chick.”