I think I can stop lying to myself and the tiny porcelain frog that passes as my brain and just admit that Levi is the perfect combination of Sexy Guy™, Handsome Guy™, and Cute Guy™. You know when you’ve been in love with someone for years, and then they do something horrible, like forgetting to water your Chia Pet unicorn or screwing your best friend, and you stop

seeing them through rosecolored lenses? All their shortcomings are thrown in sharp relief, like you just put on 3D glasses for inside ugliness? Well, now that I’ve gotten rid of my asshole goggles, I can acknowledge that Levi’s been eligible-bacheloring it up just fine. He’ll make some lucky girl an even luckier girl someday. And I have no idea why the idea of him having a live-in girlfriend sends that cold tingle in my belly—we’ve been fuckbuddies for less than twenty-four hours, for cake’s sake. It’s not my business, and the last thing I want is another relationship doomed to a messy, painful ending (i.e., any romantic relationship).

“Schrödinger didn’t like her?” He gnaws lovingly on my thumb.

“To be fair, she was a dog person.”

“When was this?” I ask, as nosy as a curtain-twitcher.

“In grad school. Before . . .” He doesn’t finish the sentence, but his gaze lingers on me for a moment, and I wonder if he meant “Before you.”

Annie used to have a funny theory: we all have a Year Zero around which the calendars of our lives pivot. At some point you meet someone, and they become so important, so metamorphic, that ten, twenty, sixty-five years down the line you look back and realize that you could split your existence in two. Before they showed (BCE), and your Common Era. Your very own Gregorian calendar.

I used to think Tim was my Common Era, but I don’t anymore. In fact, I don’t want another flaky, fickle human being to become my Common Era.

You know what would work great as a pivotal lifetime point? Me, getting my own NIH lab—which, I’m thrilled to say, is closer than ever. I almost want to text Annie to ask if new jobs can be Year Zeros, but I’m not quite there yet.

Still, it’s nice to know that I could. That the door between us is ajar.

Levi wasn’t going to say “Before you,” because I’m not his Common Era.

I don’t care to be. But I’m positive he’ll meet her soon. Probably a girl who’s five eleven, knows how to build a microwave from scratch, and has the astounding grace of Simone Biles. They’ll produce fierce, athletic kids with scarily smart brains and have sex every night, even when there are grant deadlines, even when the in-laws are in the guest room. Hummingbirds will

flock to their yard during the spring months, and Levi will study them from his screened-in porch and be implacably happy

—just like I’ll be happy with my lab, my research, my students, my RAs (Yes, they’ll all be women. No, I don’t care if you think it’s unfair).

But I’m glad I found out that Levi used to like me. I’m glad I get to have excellent sex for the first time in my life. I’m glad we’re doing this sleeping-together thing without all the ugly that comes from actually investing in a relationship. I’m glad we can be part of each other’s BCE for a while. I’m glad to be here. With him. I might even be

happy.

“I think you’re the best,” I say, ruffling the fur around Schrödinger’s ears. “He’s very small.”

“Runt of the litter.”

I smile at the perfect beany underside of his paws. “I’ve always loved an underdog. Undercat?”

“I’m surprised someone who likes cats as much as you doesn’t . . .”

“Have one?”

“I was going to say five.”

I chuckle. “There is Félicette . . .”

“I was thinking more of existing cats.”

I glare at him. “I’d love to dedicate my life to embodying the cultural archetype of the crazy cat lady. But it’s a bad idea.”

“Why?”

“Because.” I hesitate, and Schrödinger purrs against my fingers. My love for him knows no bounds. “I couldn’t take it.”

“Couldn’t take what?”

“When they die.”

Levi gives me a curious look. “Not for years. Decades, sometimes. And a lot happens between the beginning and the end.”

“But the end does happen. Unavoidably. All relationships between living beings end somewhere, somehow. That’s just the way it is. One party dies, or is called away by other biological needs. Emotions are transient by nature.

They’re temporary states brought on by neurophysiological changes that aren’t meant to be long-lasting. The nervous system must revert back to homeostasis. All relationships associated with affective events are destined to end.”

He seems unconvinced. “All relationships?”

“Yup. It’s science.”

He nods, but then says, “What about prairie voles?”

“What about them?”

“They pair-bond for life, don’t they?”

His eyes glint appraisingly, like he’s observing a fascinating biological phenomenon. We might not be talking about the misery of having to flush a goldfish down the toilet anymore. “Then prairie voles are the exception, because their oxytocin and vasopressin receptors are scattered across their reward systems.”

“Isn’t

that

biological

proof

that

emotions

and

relationships can be long lasting?”

“Not at all. So you have two cute rodents and they stick together.

Amazing. But one night husband vole crosses the highway to catch Ratatouille at the local theater and ends up pancaked by a Ford Mustang owned by a dipshit who’s driving to cheat on his wife with an unknowing college girl. Cue: grieving widow vole. It sucks, but it’s like I told you: one way or another.”

“And what happens in between doesn’t make it worth it?”

Have you ever been left behind? I want to ask him. Have you ever lost it all? Do you know how it feels? Because it doesn’t sound like you do. But I don’t want to be cruel. I’m