Photo: Noah Kalina/Noah Kalina

I have 700 friends on Facebook, 36 of whom I consider exes. Not all are ex-boyfriends—in the eleven years that “boyfriend” has been a name for men in my life, I have referred to nine as “boyfriends.” The rest are men I dated casually, guys I dated disastrously, make-out buddies, one-night stands, vacation flings, and a few boys I never touched but flirted with so heavily they can no longer be categorized as “just friends.” These people aren’t ex-boyfriends but they’re ex-something, weighted with enough personal history to make my stomach drop when they message me or pop up in social-media feeds. Which is pretty often.

There was a time, I am told, when exes lived in Texas and you could avoid them by moving to Tennessee. Cutting ties is no longer so easy—nor, I guess, do we really want it to be. We gorge ourselves on information about the lives of our exes. We can’t help ourselves. There’s the ex who “likes” everything you post. The ex who appears in automated birthday reminders. The ex who appears in your OkCupid matches. The ex whose musical taste you heed on Spotify. The ex whose new girlfriend sent a friend request. The ex you follow so you know how to win him back. The ex you follow so you know how to avoid her in person. The ex you watched deteriorate after the breakup. (Are you guilty or proud?) The ex who finally took your advice, after the breakup. (Are you frustrated or proud?) The ex whose new partner is exactly like you. (Are you flattered or creeped out?) The ex whose name appears as an autocorrection in your phone. (Are you sure you don’t talk about him incessantly? Word recognition suggests otherwise.) The ex whose new partner blogs about their sex life. The ex who still has your naked pictures. The ex who untagged every picture from your relationship. The ex you suspect is reading your e-mail. The ex you watch lead the life you’d dreamed of having together, but seeing it now, you’re so glad you didn’t.

My peers and I have all these exes, in part because we have more time to rack them up before later marriages, because we’re freer about sleeping around, because we’re more comfortable with cross-gender friendships and blurring sexual boundaries, because not committing means keeping more love interests around as possibilities, and because the digital age enables us to never truly break up. We don’t have to shut the door on anything. Which is good, because shutting the door on something is not something we ever want to do.

Alarmists fret that casual sex discourages intimacy. But in my experience, the opposite is true. When you share your bed, your toothbrush, your sexual hang-ups, and the topography of the ­cellulite on your butt with a stranger, the intimacy is real. It just happened before familiarity did. You are privy to information his family and friends are not; you know what he sounds like when he orgasms and when he snores. You may never see this person again, but he will always be your ex.

But more often than not, you will see him again. Like “dialing” a cell phone or “filming” a digital video, “one-night stand” is an anachronism. Even if you only have sex once, you will spend time with your hookup when he finds you on Facebook, appears in a mutual friend’s Instagram, or texts about a weird bump he found on his penis. Older generations didn’t have a word for this kind of thing—they couldn’t have. But these are, in fact, relationships. Even casual dates have expansive biographies to plow through and life narratives you can follow for years. You hear about their hangovers when you check Twitter for the morning news. You see their new apartments when you browse Facebook at work. They can jump into your pants whenever they want by sending text messages that land in your pocket. Online, you watch your exes’ lives unfold parallel to yours—living, shifting digital portraits of roads not taken with partners you did not keep.

There was also a time, I am told, when staying in touch was difficult. Exes were characters from a foreclosed past, symbols from former and forgone lives. Now they are part of the permanent present. I was a college freshman when Facebook launched. All my exes live online, and so do their exes, and so do their exes, too. I carry the population of a metaphorical Texas in a cell phone on my person at all times. Etiquette can’t keep up with us—not that we would honor it anyway—so ex relationships run on lust and impulse and nosiness and envy alternating with fantasy. It’s a dozen soap operas playing at the same time on a dozen different screens, and you are the star of them all. It’s both as thrilling and as sickening as it sounds.

Photo by Clayton Cubitt Photo: Clayton Cubitt/New York Magazine

My friend Anne was lying in bed with Mac, her boyfriend of six months, when an ex-boyfriend from fourteen years ago hopped into their bed. (I’ve changed some of the names in this story, not that it makes much difference.) “Hey, what’s up,” Paul texted. Anne pulled the phone into bed with her, set the ringtone to silent, and watched his next message appear: “Are you married yet?”

Because texts generally occur between two parties and on private devices, they are intimate. Because they transmit instantly and in short utterances, texts resemble conversations. But texts are also depersonalized, carrying few traces of the physical person behind them—no face, no voice, no handwriting. You cannot be certain whether a recipient is delaying a response because she is away from her phone, or willfully ignoring you. In that way, texts offer a kind of risk-free come-on.

“Not married but I have a boyfriend,” Anne replied. Paul escalated to a phone call, but she ignored it. “That’s not like you,” he texted next, revealing that he “thought he saw something” about an impending wedding. Since they live in different states and no longer have mutual friends, Anne assumed Paul meant online.

When we communicate with exes, sometimes the medium is the message. An ex who “likes” your selfies thinks you still look hot. An ex who ignores 2 a.m. texts is either asleep or over you. An ex whose jokes your friends retweet would have been popular with them. An ex who retweets you and adds a nasty hashtag is giving you a taste of the smack he talks behind your back.

Unexpected texts carry the subtext of the sender’s whereabouts and state of mind. Late-night correspondence like Paul’s may signal loneliness, horniness, or drunkenness. When a co-worker received an unexplained iPhone Facetime chat request at 11 p.m. from an ex-boyfriend she hadn’t spoken to in years, we pulled out our phones to inspect how that might happen accidentally. The Facetime option is most prominently available during phone calls and texts; since there was no call, she surmised he’d saved her texts and was rereading them. Or maybe he was looking at her entry in his address book—there’s a Facetime button there, too. But the only reason to look at an address-book entry is to share, edit, or delete it. Either her ex-boyfriend was obsessed with her, rereading old texts in the dark of night—or he was over her and deleting her forever. There was no middle ground, only unknowable extremes. And that’s what ex management feels like all of the time.

At the end of our three-year relationship, my ex stopped showing up in my Gchat contacts list. I figured he’d blocked me or gone invisible. The breakup had been acrimonious, the kind where you refuse to attend parties until you’ve been assured your ex was not invited, and even then you insist on reviewing the guest list. The entire list, please forward it to me by e-mail. He appeared again in my Gchat list again ten months later, the equivalent of making eye contact at a party, then socializing calmly in one another’s presence—a working definition of being “over it.” But there was a problem. I noticed my ex-boyfriend’s name when I was going to Gchat my boss, who has the same first name. Staring at their names lined up alphabetically, I knew the risk of an accidental message was too great. I had no choice but to block him again.

Between alphabetized contact lists and auto-complete, names invoked in digital media can be a Freudian nightmare. When I search for “Dad” in Gmail, the similarly spelled name of an older man I once dated flickers across the screen. The boss who shares a first name with one ex shares a last name with another. When I briefly dated a man with the same name as my brother, I never worried about the psychic trauma that would occur if I said his name in a sexual context. But I did worry that I might accidentally sext my brother. To be safe, I changed my hookup’s listing to his last name, but then I worried I might forget the system when drunk. Since I only sext when drunk, the fear seemed legitimate.

Just as saying “Bloody Mary” three times in front of a mirror at midnight is fabled to summon a gory ghost, using an ex’s name in digital media can summon her—sometimes literally. My friend Sam has two significant ex-girlfriends, both of whom he contacts when drunk. One ex he e-mails; after their breakup he deleted her number from his phone. The other ex he texts. He has hooked up with the text ex six times in the past year, which he credits “completely” to the ease of drunk texting. Sam wouldn’t rule out a hookup with the e-mail ex, “but who arranges a booty call by e-mail?” An informal poll of my friends in their twenties and thirties revealed SMS texting as the late-night medium of choice for the following reasons: Texts are less confrontational and thus less intimidating; rejection doesn’t hurt as much by SMS; texts are quicker and thus more prone to impulse; if you’re at a noisy bar, you don’t have to step outside. And you can text multiple people simultaneously.

They may be everywhere online, but seeing an ex pop up in a social-media feed can be as jarring as running into him on the street. I once spent an afternoon on Twitter watching an ex’s new girlfriend crowd-source assistance acquiring Plan B. “Cool,” I said. “She humped my ex-boyfriend’s naked penis last night.” To avoid unexpected mental images, I generally remove ex-boyfriends from automated social-media feeds. I have also been known to turn and run from certain exes when I’ve seen them walking down the street. It’s a fight-or-flight thing.

But that doesn’t mean I don’t cyberstalk. I’m as nosy and judgmental as the next social-media masochist; I just need to steel myself before ex encounters. And so, during afternoon lulls and late at night, I sometimes navigate to the URLs of their ­public-facing Twitter, Facebook, and Instagram feeds. I start at the top and scroll down, binge-reading backward the fractured narratives of their lives. Has his sense of humor changed? Did he finally download emoji? Who are these new people in his life? I may click their names and open their profiles in new browser tabs, the equivalent of a stack of books by a bedside table, but every book is a person’s life, and “snooping” might be more accurate than “reading.” And “fantasizing” might be more accurate still, since I’m ultimately poking around their lives to see how it might feel to live there again for a little while.

Several months after ending a relationship of five years, my friend Omar’s ex-girlfriend updated her Facebook cover photo to an image of the duo embracing on a beach. Omar found out about the photo at a party, when a friend asked if they were back together. She missed him, a shocked Omar realized. She definitely wasn’t dating anyone else. Twenty-one people “liked” the picture. “Perfect! <3,” one friend commented. Omar texted to ask about the picture. Three weeks later, they’re back together.

When her ex-boyfriend Scout extended their breakup conversation into a long thread of soul-searching Gmails, Carrie drafted two responses. In the polite version that she sent, she reassured Scout that she was fine and asked that he e-mail less frequently. In the scorched-Earth version that she saved as a “draft,” she excoriated her ex. She reread Scout’s e-mails “whenever I felt like torturing myself,” often returning to her draft, reconsidering and revising it. The process sounded, in some ways, therapeutic. Two months after the breakup, Carrie opened her scorched-Earth draft and hit “delete.”

Three months after that, she found it again. Marked “sent.”

She contacted me in a state of terror. “I scroll down and see that draft e-mail ACTUALLY SENT, on the same day I thought I erased his e-mail address from it.” As good friends do, I replied with total calm. “OH MY GOD. ARE YOU SURE??? HOW CAN THAT HAPPEN? DID YOU HIT ‘SEND’ BY ACCIDENT? DID IT JUST DO IT BY ITSELF?”

Frantically, Carrie searched for information about accidentally sent e-mails. Google’s Products Forum for Gmail is a tragicomedy of desperation, populated with unreliable narrators. “I have to cancel a sent e-mail!!! Please help me, emergency!” pleads Gmail user Artbygbs. “Please help, it’s a life and death situation,” says Lauritadr21. “How do I delete a message so that the person I sent it to doesn’t see it?!” asks the Google account of a synagogue.

In nearly every case, the crowd-sourced answers are the same. “There is no way to recall a message once it has been sent. Sorry.”

“I’m sure it was because when I thought I was deleting his e-mail while drunk at a bar, I was actually sending it,” Carrie said via Gchat.

“Wait, you were drinking?” That seemed relevant, but we did not discuss it in detail because, moments later, I changed the topic with force. “OMG WAIT MY COLLEGE BOYFRIEND GOT MARRIED TWO WEEKS AGO AND I MISSED IT.” I copied and pasted the URL of a Facebook photo from the ­ceremony, which took place in Texas.

Three months before I discovered his wedding photos on Facebook, I had received a Facebook message from a friend of my college boyfriend: “I am at Jason’s bachelor party and we are roasting him tonight.” He was gathering stories, so I recounted everything I knew about Jason’s childhood teddy bear.

That night, Jason sent me a friend request on Snapchat. It was 1:30 a.m.

“It seems odd that at the beginning of the Internet everyone decided everything should stick around forever,” Snapchat co-founder Evan Spiegel noted months after the launch of the app, now the preferred messaging client for sexting because messages are photographs and designed to self-destruct after a few seconds. “It’s about the moment, a connection between friends,” Snapchat’s website says. “Enjoy the lightness of being!”

The Czech novelist Milan Kundera coined the phrase “the lightness of being” in 1984’s The Unbearable Lightness of Being. He meant it as a counterpoint to “the heaviest of burdens,” Nietzsche’s idea of eternal return: “If every second of our lives recurs an infinite number of times, we are nailed to eternity as Jesus was nailed to the cross,” he wrote. “It is a terrifying prospect. In the world of eternal return the weight of unbearable responsibility lies heavy on every move we make.”

When we talk about sexual history, we often talk about “the number,” a quantification of sex partners that haunts or ennobles. But when I asked my friends, I found their running naked-picture tallies were just as readily available—if not more available. My friends were polarized: Either the number was so low it could be counted on one hand, or it was too high to count. “Hundreds?” one offered.

Sending a message designed to self-destruct is like prefacing a conversation with “Can you keep a secret?” or pausing a make-out session to turn out the lights. Tawdriness is not guaranteed, but its possibility is part of the fun. Not that it’s always wise. I wrote my reply to Jason on a piece of paper and snapped it back: “NO GOOD can come from a soon-to-be MARRIED MAN friending an ex on SNAPCHAT.” His defense: “It was only 10:30 my time. Also you’re wrong about Snapchat.”

I asked my friend Sam, who is also my boyfriend’s roommate and a blogger. After going through sexting and visual-prank phases (he once snapped a picture of his poop to gross out a girl), Sam says he now uses Snapchat for “visual check-ins”: “If I snap a picture of my chicken broth, we both know we won’t care in a few hours, so better not to save. Why bother?” Snapchat was sexy at first, then shockingly comfortable, then rigorously mundane. This was, I realized, the same pattern as sexlessness creeping into a long-term relationship.

I have a friend who tried to erase an ex-boyfriend. They dated for two months, until he dumped her using a technique known as “the fadeaway”—“just blowing me off repeatedly after all of this intensity,” Celia said. His online presence became salt in her wound, “tormenting me by tweeting every five seconds.” Even when she stopped following him, she could not escape the retweets.

“So I tried a few different things—the best is MuteTweet, which for the most part keeps him out of my timeline.” Celia blocked him on Gchat, removed him from her Facebook feed, and installed a web-browser plug-in called Ex-Blocker, which makes sure no reference to the supplied names appears in Firefox or Chrome. For those who want to erase history, KillSwitch crawls your Facebook photos, videos, and wall posts, systematically deleting anything that mentions your ex. For those who lack willpower, Ex Lover Blocker activates a phone tree of your best friends when you call your ex. (If you try to work around it, Ex Lover Blocker resorts to public shaming on your Facebook wall.) There’s even something called Eternal Sunshine, which removes unwanted status updates from your Facebook feed.

But how boring would that be? I thought as I poked around looking for the ex whose then-girlfriend had crowd-sourced birth control.

“Did you quit Facebook?” I e-mailed him. “OR DID YOU BLOCK ME???”

“Quit in January!” he replied.

With the help of cell-phone records and Google archives, I deduced that we had nonetheless been in touch sporadically by Gchat, Gmail, Twitter, and text messages, including one inter­action where I pouted, “Talking to you isn’t fun anymore.” His response was to tell a story about peeing his pants, and another about “coffee-farting” in a boardroom. “You are sort of fun to talk to, as long as I’m not eating a snack,” I replied. I realized this was, probably, my platonic ideal for ex relationships: a little amusement, some catching up, and a small reminder that, yes, my personal history did happen. But then it ended and we both moved on. Sort of.

*This article originally appeared in the July 29, 2013 issue of New York Magazine.