(The Washington Post illustration/iStock)

It was at Costco that Justine Chen realized she was in love.

“I would never do this for anyone else,” Chen told her boyfriend, while accompanying him for an eye exam there on a Saturday afternoon. It was sweaty and crowded, the wait longer than expected. And yet — rather than feel bored or aggravated over hours wasted on someone else’s errands, she was perfectly happy in that beige, soulless warehouse in Glendale, Calif. It hit her during that trip, plus a follow-up the next weekend to pick up his glasses, that she didn’t just like this guy. She loved him.

Yet Chen, 34, did not pronounce those words for the first time while surrounded by eight-pound bags of oranges or supersize jugs of protein powder. She held on to them for months.

In the meantime, Chen’s “Wow, I love this guy” euphoria spiraled into “Is it too soon?” anxiety. Like a good millennial, she Googled: When is an appropriate time to say “I love you”? Though Chen’s research confirmed that their relationship was within the socially accepted range of three to six months, she waited. They took an out-of-town trip together, and still, she waited.

You might think: Just say it already! But there are no guidelines for when to pull the trigger. I’ve spoken to people who said it on a first date (don’t worry — they’re happily married!); within the first week; the first or second month; almost a year. Several people told me they’ve felt embarrassed or “behind” to be saying it for the first time in their late 20s or early 30s. When I told a dating coach I haven’t said it romantically in 12 years, she became alarmed and offered me her services.

In the past decade, the anxiety over when to say “I love you” has been amped up by dating apps and sites, which make it increasingly easy to connect and disconnect. With more options, it’s that much harder to find a match that lasts. Promising connections fizzle and disappear, often without warning or explanation. It can take couples three to six to nine months to decide to be exclusive, let alone feel ready to say “I love you.” Saying those three little words to a significant other has become a bigger deal than ever before.

It’s not that daters aren’t vocal about what they mean to one another in words, actions — and, unfortunately, inaction. Rather, it’s that the expectations and assumptions surrounding this phrase have become so overblown. Through conversations with numerous daters and experts, it’s clear that many of us would benefit from turning down the pressure — and conveying what we feel when we feel it.

(The Washington Post illustration/iStock)

Chen and her boyfriend broke up a few months after that Costco trip — and she regretted not saying it. When they got back together, she didn’t waste time. “I just wanted to tell you that I love you,” she told him in a phone call. “And I don’t care whether you say it back or not.”

Her boyfriend did not say it back, but he was honored she felt that way, he told her, adding that when he says it back, “it’s going to be special.”

“If it was a different situation where he got freaked out and backed off — or wasn’t showing that he cares — the relationship would probably fall apart,” Chen says. Still, after saying it twice, she shelved her “I love yous.”

“I love you” gets said between family members and among friends, but the romantic “I love you” is the most fraught. “Men and women are scared to take that step and be that vulnerable,” says Jess McCann, a dating coach in Washington. For daters in their late 20s and 30s, she adds, “I love you” often means, “We’re getting married.” There’s a sense of: “I need to be sure, because this could mean forever.”

No wonder Chen’s boyfriend was taking his time. It was his first serious relationship since a broken engagement, she says, so he was deliberate about every stage. Chen, on the other hand, was so fed up with today’s noncommittal dating scene that she’d rather be emotionally expressive. Unfortunately, they’re no longer together.

Not being in sync doesn’t necessarily kill a relationship. “Even when people hear crickets back, most people do not pack their bags and move on,” McCann says. She’s seen people stick in a relationship for six months to a year, waiting for an “I love you” to be returned.

Generally, women are waiting for their male partners to say it first, dating experts say, because men are still the ones driving most heterosexual relationships forward. But that convention is slowly changing. McCann notes that many of her female clients consider saying “I love you” first in part because they want an answer to the question: Do you love me? “They just have no idea where the guy stands,” she adds.

When Cristina Batista, a 28-year-old queer woman in Washington, has dated cisgender men, she’s waited for them to say “I love you” first. Now she’s seeing someone who’s transmasculine and nonbinary, and she said it first. “That was pretty scary,” she says, though “it was nice to break out of that expectation.”

Michael Levkowitz, a 30-year-old in Seattle, told his girlfriend, Meredith, that he loved her after four or five months, shortly after they’d become exclusive. “I stared at her for 20 seconds, and I couldn’t avoid saying the words,” he recalls.

She reacted as if he’d jumped the gun. “You fall in love too quickly,” she said dismissively before turning over to go to sleep.

“That’s kind of hurtful,” he told her. Levkowitz knew the feeling was mutual. But he thought she believed that by saying those words, “you formalize commitment or intent,” thereby raising the relationship’s stakes.

When he pressed her on it later, “she was willing to admit that she was in love with me,” Levkowitz says. “It was more of an admission of love than a proclamation.”

Sometimes these overtures are left unreturned not because two people’s feelings are grossly mismatched but because they express them in different ways. The five “love languages” were first detailed in a best-selling self-help book from the 1990s and have since become a cultural phenomenon. Levkowitz shows he cares through “words of affirmation,” he says, while Meredith, who’s now his wife, likes “quality time” (the others are “gift-giving,” “acts of service” and “physical touch”). Levkowitz says, “It took some time to adjust.”

How you say “I love you” really does affect what it means. Levkowitz credits his grandmother with teaching him to say it with intention. “She hates the way people rushed to say ‘I love you’ at the end of phone calls,” he says, so they often have long goodbyes over the phone. He likes to pause, to give the phrase more space and heft.

But painstaking “I love you” calibrations can just end up feeling cruel. Briallen Hopper, author of “Hard to Love: Essays and Confessions” and an assistant professor of creative nonfiction at Queens College at CUNY, recalls a boyfriend from her 20s who ruined “I love you” for her. He didn’t want to cheapen it by saying it all the time, she says, so he would say it only if he was “feeling a wave of love.” She did the same — but if he wasn’t feeling the same rush of warmth, he wouldn’t reciprocate.

“In theory it was coming from a romantic place,” Hopper says. “In practice, it turns out our waves of love didn’t sync all the time. Then I associated [I love you] with not so much being in a solidly loving place.”

Caleb Pate, a 27-year-old man in Washington state, has another kind of “I love you” wound. He had an unhealthy relationship where he said “I love you, too” less out of genuine affection and more because he didn’t want to hurt his partner. So in a new relationship, when his boyfriend said, “I love you,” Pate paused, mulled it over and took about a week before he spoke those words during an airport goodbye. “I wanted to make sure I was responding from my own confidence in that sentiment, instead of obligation,” Pate says. His current boyfriend, Camren Davis, 34, says he’s taking care to “guard the phrase” from becoming an “unconscious splurt.”

If there’s any argument for loosening up on our “I love yous,” it’s the healing power of saying it when we don’t even want to hear it back. Brian Bernfeld, a 25-year-old pilot based in Florida, told his ex-girlfriend that he loved her — but only after they’d broken up. He said it not because he wanted to get back together, or wanted her to reciprocate, but because he needed to be honest with himself. “If you don’t say how you feel, you’re never going to get past it,” Bernfeld says in a phone interview. Just the act of texting her “I’m still in love with you” helped him get closure and move on.

(The Washington Post illustration/iStock)

How did “I love you” become such a big deal? One theory is that it’s God’s fault. Simon May, a visiting professor of philosophy at King’s College in London, credits the Judeo-Christian tenet of loving God with all one’s heart, soul and strength as establishing love as the most important thing in life. It wasn’t always this way: Back in ancient Greece, for example, courage was the value vaunted above all else. But “if God is love,” May says, “then our lives were oriented toward love.” As Western culture became more secular, starting in the 18th century, “human beings had to take over this enormous value — love — and give it to each other,” he says.

That’s part of the reason we have such high expectations of our romantic partners. “We’ve been judging human beings by divine standards,” he says. More recently, however, May thinks love is coming back down to earth. “We’ve come to realize . . . that we have expectations of romantic love that have been completely unrealistic.” We’re just starting to accept that true love doesn’t have to last forever.

Obviously, there are other cultural factors at play, and every country has its own unique relationship with “I love you.” In France, the phrase isn’t guarded as closely as in the United States, as Adeline Bréon, a dating coach who was born in Paris, wrote in The Post . In Iran, for example, it’s considered a formal step toward marriage, according to Sholeh Wolpé, an Iranian American writer and literary translator. And in South Korea, older generations didn’t say it so much, writes Stephen Epstein, a professor of Asian languages at Victoria University of Wellington, New Zealand. But as Western conventions have caught on, younger generations are starting to use it more freely.

Telling someone you love them is a big milestone for many relationships, sitcom couples included. But that doesn’t mean things don’t get awkward from time to time to time. (Allie Caren/The Washington Post)

Before we’ve experienced romantic love for ourselves, Hollywood gives us specific rules about what it looks and sounds like. Such as: Men are supposed to say “I love you” first. Saying it too soon or not hearing it back can doom a relationship. Remember when “Seinfeld” declared the unrequited “I love you” as akin to a “big matzo ball hanging out there”? Or in “Gilmore Girls,” when Dean mustered up the courage to tell Rory he loves her and she responded with a blank face, stammering “I . . . I . . . I love the car.” Or on “That ’70s Show,” Donna says, “I love you, Eric.” “I love . . . cake.” None of those pairings lasted. But comedies can do a decent job pointing out that love isn’t so perfect. A misfire doesn’t always ruin the relationship. In “How I Met Your Mother,” for example, Ted is consistently mocked for telling Robin “I think I love you” on their first date. But by the end of the series, they end up together.

Movies and television also show that it’s not just words that matter. “Back in the great Hollywood era, saying ‘I love you’ was corn,” says Robert McKee, a screenwriting guru and the author of “Story.” “They’d much rather people in the audience think, ‘Oh, he loves her.’ ” McKee points to “Casablanca” and the way Rick sacrifices his own happiness and safety to help his former flame Ilsa and her husband flee the Nazis. That grand gesture, plus a nod to their shared past (“We’ll always have Paris”) and his concern for her future (“Here’s looking at you, kid”) are Rick’s way of saying he still loves her.

Which should provide some consolation for daters like Chen — and for all of us, really. “I love you” shouldn’t have to mean: We’re getting married. It can simply mean: I will sit in Costco for as long as it takes to get that eyeglass prescription. And I would come back the next weekend. Because I know you’d do the same for me.

This story has been updated.