When my son's dad moved out, we thought our relationship was over — but we're still family

• My son's father moved out of the house he lived in with me and our son. 
• I thought it would be the end of our relationship, but we still spend a lot of time together. 
• It was hard to know what to label our connection at first, but in the end, we're still family.

When my son's father moved out of the house we shared with our 3-year-old, he took his shoe collection, some pictures, and old Father's Day cards. Everything else, he left: his motorcycle, the air fryer his mother had bought us, the cigar box where he kept a stash of $20 bills. Even clothes, so many that I wondered what he planned to wear — until he came over the next day, took a shower, and put on a fresh T-shirt and shorts, as though nothing had changed.

I figured he was just taking time to adjust. I'd wait a few weeks, then have a candid conversation about boundaries. I told myself this until the toilet stopped flushing, and I called him frantically, wondering if there was any way he could come over that night to fix it.

We had told everyone we were breaking up. And so even as the weeks became months and we kept cooking meals together, checking in about minor life decisions, and showing up at each other's houses outside child drop-off times, we continued repeating the same story: that we had given it a good try, but failed. That we had once been a family, but now, we were not.

We continued to spend time together after we separated

What ensued was an odd kind of double life. He wasn't in the family Christmas card, but he was over for the entire holiday. I was a single mom, but my best friend just happened to be my son's father. It was hard to self-identify because every term I tried out seemed misrepresentative of our particular arrangement.

Part of the issue was that our arrangement ebbed and flowed. When I started dating someone, he and I had to negotiate expectations. We still saw each other, but we scheduled it a little more in advance — a planned weekly dinner with our son, rather than a spontaneous movie on a Wednesday night.

Even when neither of us was seeing anyone, we still sometimes crossed our own boundaries and got sick of each other. When this happened, we divided time with our son and did our own thing for a while. Two households cost more than one, but there were no other downsides to living apart. The benefits — space, and freedom — were huge and expansive, impossible to put a price on.

We didn't know how to label our relationship

It turns out, though, that society appreciates standardized labels for our relationships with the people with whom we have children. When registering our son for kindergarten, we discovered that because we did not have a shared address or a formal custody agreement, only one legal parent could be listed on the form. To be allowed to pick our son up from school, my son's father had to self-identify as a "relative or family friend."

This was annoying. But it also made me realize something. Three years after "separating," he and I were, in the simplest terms, relatives — family. We were partners to each other in most things concerning our son, and emotional and logistical partners in other ways, too. We took trips together. We bought each other things like coffee and laundry detergent. We texted every day. Sometimes, when we felt like it, we slept over.

We just weren't exclusive life partners in the way we'd tried to be before. We both spent more time pursuing independent friendships than when we had lived together in a somewhat claustrophobic home. We could each date if we wanted to, although most of the time, this didn't feel like a missing puzzle piece.

"Family" is what we call each other now. Partner, too, when it applies — or when it makes a bureaucratic phone call easier. "My son's dad," I say sometimes.

But ex-boyfriend? I haven't said those words about him for years. Because there's no "ex" about it — we're doing life together, apart. And we're grateful for it.