I Kissed Dating Goodbye opens with an unforgettable scene. A bride is walking down the aisle toward her beloved on their wedding day. Stained glass, string quartet: Everything is perfect. As the couple begins to say their vows, a woman in the congregation stands up and walks toward the front of the church, silently taking the groom’s hand. Then another joins them, and another, and another, forming an ominous chain at the altar.

“Who are these girls?” the bride asks her groom, tears welling in her eyes.

“They’re girls from my past,” he answers. “They don’t mean anything to me now, but I’ve given part of my heart to each of them.”

Then the bride wakes up.

The reader would have had no trouble interpreting this nightmare: When you have sex before marriage, the mistake sticks to you forever. I Kissed Dating Goodbye, written by Joshua Harris and first published in 1997, argued that traditional dating was “a training ground for divorce” because it puts people in the habit of quitting relationships when things get tough. Aimed at teens and twentysomethings, the book discouraged teen relationships and proposed that courtship, in which a couple moves purposefully toward marriage with their parents’ blessing and involvement, was a superior model to dating. And it argued that any kind of physical intimacy before marriage was a violation of the sacredness of married sexuality, and could lead to lifelong regret.

Published at the height of the 1990s purity movement, which emphasized the spiritual, physical, and psychological importance of abstinence before marriage, I Kissed Dating Goodbye became a phenomenon in conservative Christian circles. It inspired both praise—from the likes of purity matriarch Elisabeth Elliot and Focus on the Family—and book-length rebuttals. Harris was already a popular speaker at conferences for Christian home-schoolers and had started his own magazine, but the book’s influence quickly outpaced its modest built-in audience—it has sold more than 1.2 million copies to date.

I Kissed Dating Goodbye made abstinence seem both romantic and noble. You weren’t just not having sex, you were adopting “a revolutionary pattern of living” that would make you both a better Christian and, someday, a better spouse. It was even better not to even kiss before you got to the altar, Harris suggested, and beware of “emotional hookups,” too. He shared scary and supposedly true stories like Ben and Lisa’s: Christians who dated seriously, had sex, eventually broke up, and years later still “expressed emotional trauma and guilt.”

Harris was 21 years old when he wrote I Kissed Dating Goodbye. He was a virgin who had been home-schooled his whole life—an unusual profile for the author of a book proposing “a new attitude toward romance and relationships,” as the subtitle put it. He married at 23 and later served as the pastor of an evangelical megachurch in Maryland for more than a decade. Over the years he wrote more books about dating and marriage, including Not Even a Hint: Guarding Your Heart Against Lust and Boy Meets Girl: Say Hello to Courtship. Nineteen years after I Kissed Dating Goodbye, he is the father of three kids—two of them teenagers—and he is pursuing formal education for the first time in his life. And these days, he’s having very mixed feelings about the book that turned him into a Christian celebrity.

“Part of the reason this has been so hard for me is that I have so much of my identity tied up in these books. It’s what I’m known for,” Harris told me recently from Vancouver, British Columbia, where he moved his family last year to enroll in a graduate program at evangelical Regent College. “It’s like, well, crap, is the biggest thing I’ve done in my life this really huge mistake?”

Harris’ conversation with me was part of an ongoing not-quite-apology tour in which he is grappling earnestly with the legacy of I Kissed Dating Goodbye. Last month he gave an interview to NPR in which he said he is re-evaluating the book’s impact, and he has been responding to critics on Twitter and having phone conversations with some of them, too. A few months ago, he started soliciting messages on his website from readers about how the books affected them. So far he has received more than 300 submissions, ranging from reflective to raw. In the fall, he hopes to embark on an independent study in which he’ll read about the religious culture that informed him as a young man. “I want to do more than just say, ‘Oh, I should have said a few things differently,’ ” he said. “I just need to listen to where people are before I come out with my own thoughts. … I don’t have all the answers yet.”

I Kissed Dating Goodbye wasn’t just a book people read; it was a book they obeyed. It prompted some people to marry the first person they dated, even if they were unhappy together; to view the opposite sex with fear and suspicion; or to be afraid of starting any relationships at all. Others have struggled with viewing sexual abuse as evidence they were tainted. As one recent response on Harris’ site put it, “I feel the only man I deserve is one who is broken like me.”

Harris’ book was published as the “True Love Waits” abstinence campaign was gathering steam—the era of purity rings and abstinence rallies and books like And the Bride Wore White: Seven Secrets to Sexual Purity. I was 17 when I Kissed Dating Goodbye came out, and everyone I knew in my upper-middle-class evangelical community in suburban Chicago was talking about it. For me as a teenager, the whole topic had a pleasing ratio of certainty to ambiguity. The foundational “fact” of purity culture was that having intercourse before marriage was wrong. There was a reassuring black-and-white quality to that stricture, with the promise of a juicy wedding-night reward for my self-control. As for everything short of intercourse, I spent hours with my youth-group friends applying Talmudic analysis to the question “How far is too far?” It was an excuse to talk about sex and imagine we were really talking about God.

Two decades later, the teenagers of the purity movement have had time to date, marry, have sex lives, raise children of their own, and divorce. They have confronted the movement’s legacy online, communing about what it meant to grow up believing that even sexual thoughts must be squashed to please God. Books like Dianna Anderson’s Damaged Goods: New Perspectives on Christian Purity and the documentary Give Me Sex Jesus (both released last year) have revisited the effects of 1990s purity culture through the stories of people who lived through it. Harris’ recent public wrestling with his own work has spurred a new round of criticism from people who have been psychologically and spiritually hurt, some of whom now feel alienated from the church as a whole.

After Harris posted his call for reader reactions, a group of critics started soliciting responses at “Life After I Kissed Dating Goodbye” to “keep the power of the stories in the hands of those they belong to.” In June, the Toast hosted a roundtable discussion on the book’s impact headlined “Recovering From I Kissed Dating Goodbye.” “The idea that is so insidious in IKDG is the idea that our bodies are our power—that as a woman the best gift you can give to a man is your virginity,” writer Lyz Lenz lamented. Last month the hashtag #KissShameBye became another place for people to share their stories about how the book affected them:

Each new experience Ive had has made me angrier bc nothing is like they said it would be. It's MUCH better but I'm still angry #KissShameBye — Emily Joy (@emilyjoypoetry) July 18, 2016

Even some readers who have remained firmly rooted in the evangelical community have come to be critical of Harris’ approach. “For the love of Joshua Harris, just please stop,” read a magazine column last year urging Christian men to quit with the lofty “marriage material” rhetoric and just ask women out on dates already. As an article in the conservative Christian magazine World put it in 2011, “Even Christians who don’t like the book feel forced to color within the lines Harris drew.” In other words, even those who don’t want to “kiss dating goodbye” will likely find themselves having to explain why not. In that article, World writer Susan Olasky interviewed students at an evangelical college who said the book was so convincing in its arguments against casual dating (e.g., “Intimacy without commitment is defrauding”) that many young people who read it are now afraid to pursue relationships at all unless they know they want to marry the person, which leads to a kind of paralysis. One student told Olasky that the book led her peers to “think we should never hang out unless we want to marry. In the 1990s, casual dating was the culprit. Christian couples will rush into relationships, saying, ‘we intend to marry,’ because they think they are not allowed to date unless they intend to marry.”

Harris has absorbed these criticisms over the years but says he hasn’t had the bandwidth to respond to them until recently. Quitting his high-pressure job to start school was one step, and so was seeing his children become teenagers. “What I was writing about was ‘Avoid this pain, avoid these mistakes, don’t do these things,’ ” he told me. “Is that really how we grow as human beings?”

He still believes in the mainstream evangelical sexual ethic that says sex is reserved for heterosexual marriage. But he has come to question many assumptions that undergirded his book: the urge of parents and church leaders to strictly control young people; the purity movement’s implication that sexual mistakes are somehow irrevocable; and his book’s “formulaic approach to relationships that somehow guarantees a happy outcome.” He now draws a line between Biblical principles and Biblical practices: The former are essential (e.g., raise your children to know God) and the latter are optional (e.g., home-school your children). Christian leaders like himself have erred, he said, when they blur the two.

While he ponders these things, Harris has been posting the feedback he has received to his own site (with the writers’ permission). While some of the responses are supportive, others are blistering:

I have been married to my wife for over seven years. We’ve been together over ten. We have a beautiful daughter, and successful careers. When we were dating, we had sex. Because of the shameful purity movement rhetoric we learned from your book, sex became tainted. To this day, I cannot be intimate with my wife without feeling like I’m doing something wrong. Sinful. Impure. We both adored your book as young people. And I believe our diligent commitment to your ideas, and our “failing to stay pure until marriage” has permanently damaged our relationship. Years of truth and counseling later, I cannot get the subconscious idea out of my head that I am doing something wrong. Damn you.

“I know in many ways it’s too late for me to fix something for people who feel like they’ve been hurt by the books,” Harris told me. In almost an hour of talking about the negative impacts of the work he is best known for, he never sounded dismissive or defensive, and he didn’t use his youth or inexperience as an excuse for his book’s flaws. He spoke slowly and carefully, returning over and over to the theme of his own readiness to listen to his critics. It’s worth noting that Harris is media-savvy to avoid saying anything too definitively apologetic. But after making his name spouting certainties, there is a certain poignancy in his willingness to be nakedly hesitant in public.

Of course, many of his critics still long for more: sweeping remorse, a blistering self-damnation, a statement that acknowledges causing hurt rather than simply invoking “people who feel like they’ve been hurt.” Harris might provide them with all of that someday soon, or he might not. In the meantime, those critics are well-trained in the art of waiting for what they want.