I woke up on the morning of my 30th birthday naked and alone in an unfamiliar hotel room, with a dead phone, covered in peanuts. As I crawled around the room, desperately searching for a phone charger, I attempted to piece together memories of the previous evening. All I could think was: This is 30? I realize that 30 isn’t “old.” Still, each milestone age is inevitably approached with some anxiety, because it forces us to assess our lives and our achievements and our bodies and our relationships, and basically to compare our worth as a human being to that of all of our peers. And that’s annoying.

But back to the day itself. On my birthday eve, I had dinner plans with a 36-year-old lawyer from D.C. About a year ago, the lawyer met a close friend of mine on OkCupid, and the two had a really fun night out. But at some point during the date, my friend decided that if she couldn’t imagine sleeping with this hot, sweet, successful guy, she had to finally admit to herself that she really was a lesbian. Instead of scheduling a second date with him, she just gave him my number. “If you like me, then you’ll like my friend,” she said, “because she’s basically me but blonde and half-straight.”

A couple weeks later, the lawyer and I met for drinks in Soho—my first and only blind date—and really hit it off. Since then, we’ve met up whenever he has come to town on business, and when my relationship was in one of its “open” phases. (My ex and I opened and closed our relationship more often than I changed my sheets, which says something about our romantic turbulence, as well as my personal hygiene.) I suppose it’s a bit of a red flag that he has always refused to tell me his last name, but he’s hot and seems harmless enough (he does ballet as a hobby), so I’ve just stopped asking questions. A few hours before the last dinner of my 20s, I got a text from him: “Hey so I reeeally want you to meet my friends. They’re a married couple who swing! I think you’d get along. Mind if they crash dinner?” Followed by a salsa-dancer emoji. I said “Fine,” and the martini emoji, and headed to meet them for dinner at Narcissa, at the Standard East Village, where the lawyer always stays.

The couple were in their mid-30s, he an all-American sensitive jock type who looks like a young Christopher Reeve, she a cute, dimpled blonde with a full sleeve of tattoos. They both work in finance. They’ve been together for more than 10 years, open for six. They want to be together for the long haul, they said, and after reading Sex at Dawn, they came to think that having one partner for life just wasn’t realistic. (In the ’90s, people read the Atkins diet book and shunned carbs. Today, people read Sex at Dawn and shun monogamy.) The lawyer kept rubbing the back of my neck affectionately, as if we were actually dating. He ordered another bottle. Now, maybe I was being naive—or plain dumb?—because I hadn’t picked up on any vibes about the evening from the lawyer’s texts. But once I was two drinks deep, it suddenly became very clear that we were on a date with this other couple, and that the three of them had been plotting this for some time. I started nervously chugging my prosecco.