I’ve never believed in The One. In the long stretches of my 20s and 30s when I was single and looking for a partner, I never felt incomplete because I wasn’t in a relationship. I wanted a partner, but never felt like I needed one.

So when I met my current boyfriend in early 2012 and we started getting serious, I was thrilled. I continue to be amazed that our relationship has lasted four times as long as any of my prior ones. I love our very stable adult life. Before him I’d only foraged for furniture. I never cooked, eating takeout and frozen meals exclusively. I lived paycheck to paycheck, and I was an active hoarder.

But one vital element is missing: kids.

Being childless feels far worse than being single ever felt. I truly do feel like someone is missing from my life, and until I meet him or her, I will always be searching.

This feeling crystallized at a recent potluck at my friend’s son’s preschool. I was helping clean up, smiling as the kids received balloon animals. A little girl, probably a year old, wanted some water; her mom was handling the balloons, so I opened a bottle of water and held it to her lips. I struggled to find the right angle, not wanting to tilt it too high and dump water all over her. She wasn’t speaking yet, so she communicated only with her sweet wide brown eyes.

In the minute or so that I helped her to those gulps of water, which still managed to spill down her dress despite my carefulness, I felt an overwhelming urge to pull her close and give her a hug. Her mix of delicateness and strength, her ability to communicate nonverbally, her gorgeous eyes staring back at me as if we weren’t strangers, all completely sucked me in.

If I could feel so much for a child I didn’t even know, who belonged to someone else, how much love would I have for a child I named and fed and cared for every day? That question haunts me.

Recently, my great-aunt asked me why I want to have kids. “I know you want to, I just don’t know why,” she said. It’s a shockingly personal question that no one had ever asked me. I struggled momentarily for a response before settling on: “I feel like I have all this maternal energy to give, and it doesn’t have an outlet.”

Perhaps that doesn’t sound as passionate as women who are completely sure — from the time they were pushing dolls in carriages — that they were born to become mothers. But it’s the truth. I think about it when I pack lunches for myself and my boyfriend each morning, parceling out pretzels into baggies, placing his favorite snack bar in his bag and mine in my own.

I usually wake up at 5 a.m., so I have a lot of quiet time to think. Those are the moments when the lack in my life hits me the hardest. I long for a sleeping baby, or toddler, or even a teenager, to check on first thing before the sun’s up, whose hair I can ruffle, whose life I can help shape and plan.

Sometimes my boyfriend accuses me of wanting to be a mom just because I love babies. I can’t deny that I do adore infants’ unique smell, their warm, tender bodies seemingly made to be held, the way their needs are so simple. But my desire goes far deeper.

When I was single, I always felt that I’d be fine living an independent single life, maybe with a friend with benefits on call. Marriage has never held any kind of allure to me. Sure, there were times I bemoaned dates gone awry and was lonely, but I never felt an urgent need to find a partner — any partner — ASAP. If I found someone, great. But if I didn’t, that would be okay, too.

So this feeling of raw need regarding children has shocked me — and made me rethink my judgmental attitude toward women who feel the same way about finding a significant other. I’d always scoffed at women and men obsessed with walking down the aisle. I looked down on them for not valuing themselves enough to be happy on their own — until, in a way, I became one of them.

“Baby fever” may sound absurd, but when you’re in the grips of it, it feels very real, perhaps the fertility version of being a “bridezilla.” The sense of sadness, fear, uncertainty and powerlessness that becomes entwined in searching for another person to join your life strikes me as remarkably similar. Now that I’ve become someone willing to drop $10,000 on fertility treatments, I can no longer belittle anyone paying similar amounts for matchmakers.

Sometimes I wish all I were looking for was another adult, rather than a child. At age 40, that second quest seems much more daunting.