On Sunday I saw Daughter No. 2 off to college. It was nuts. I mean, it wasn’t nuts — this wasn’t aberrant or unsettled behavior, and aside from the traffic heading into Manhattan, it wasn’t likely to incite violence — but on the other hand, it was nuts. These separations from my children always feel nuts. It felt nuts seeing Daughter No. 1 off to Ecuador for her gap year, nuts seeing her off to college 12 months later. For that matter, it was nuts seeing both of them, and their younger brother, too, off to pre-K. It was nuts kissing their moist heads, inhaling their fresh, intoxicating eau de enfant, and leaving them for the first time with a babysitter. It was nuts each time I left one of them in a crib and shut the door for the night. Nuts.

From the moment of spasmodically painful, downright sloppy and altogether ludicrous squirting-out that we call birth, we’re ripped in two by the seismic rupture that violently separates mothers from children. We spend nine months carrying them around, caring for their every need, feeling their every jolt of an elbow or heel inside us, and then: boom. They leave. It’s awful. And beautiful. And awful. And life-changing. And awful. And nuts.

Parental love is truly a form of madness. It changes everything. It alters your view of the world, your ordering of priorities, your reason for being, your definition of love, your willingness to fight and live and die for another human being, and your tolerance for Barney, sleeplessness, Barney, screaming, Barney, vomit, pee and shit. Not to mention your tolerance for getting vomited, peed and shat on. Simultaneously. On three and a half hours of sleep. While watching Barney. And loving every minute of it, even when you’re not.

The days of shit and Barney don’t seem so long ago. The tug of an infant at my breast, the scrape of a stroller against pavement, the scare of a burning forehead in the middle of the night: these aren’t memories. They’re presences — pressing, pulling, sensory realities with a weight and force that remind me, as if I could forget, that my love for my children is more solid and immutable than the aging frame that bore them.

Hugging my daughter goodbye on Sunday, I held her face in my hands as I hadn’t since she was tiny, and I marveled — as I so often do when I regard my kids — that a creature of such beauty entered the world through me. What if I’d refused to let her go, way back when? What if I’d shut the gate and barred her from passage? Would she still be stuck inside me?

I had to let her out. I had to let her leave me. I couldn’t make her stay.

But still. It’s nuts.