"Love is like a fever which comes and goes quite independently of the will."

--Stendhal

A black-and-white photograph falls out of your college dictionary, frayed at the edges, faded and creased. Yet the face is indelible, with its lopsided grin that still takes your breath away a lifetime later. A lock of hair falls over his eyes, like it always did when you walked the Northern California beaches that summer of 1976, the summer you were inseparable, intoxicated by a first love so intense you couldn't eat, couldn't sleep, couldn't do anything but be with him, you just had to, or you felt like dying.

In the summer of 1999, holding a small child's feet in the surf on a beach on the other side of the country, a magnificent husband by your side, you feel the salty air hit your cheek in a way that slaps you back into that moment of splendor with The One Who Got Away, the boy who took you from girl to woman, a 20-year-old who loved Fleetwood Mac, the guy you left in Santa Monica nearly a quarter of a century ago but time has failed to erase.

What is it with old loves? Just when you have finally forgotten them, which may take decades, something happens--the smell of fresh pine, the throb of the ocean, a snapshot found in a drawer, and you're back at college graduation, when the two of you swore you'd get back together someday, this time forever, after you made something of yourselves and saw something of the world. Years passed and one person's head got turned in another direction, and the other person got tired of waiting and you are both spending forever with someone else.

But The One Who Got Away still makes you wince. He still haunts you in an occasional dream. You hate yourself for being compelled to locate him through detective software designed to "find anyone, anywhere," and your chest tightens when his name comes up on your computer screen, complete with e-mail address. Should you send a friendly greeting?

"Hi, remember me? I was once the love of your life. What's happening?"

I'll never forget when my college boyfriend called 15 years ago to tell me he was getting married. I didn't want to marry him but I didn't want anyone else to marry him, either. When I hung up, there was a jagged rock in my gut. That conversation signified the end chapter in an ever-mysterious, always tantalizing, on-again, off-again relationship that for a decade simmered in the spirit of "someday, maybe." Now, there was no more mystery, no flicker to kindle back to a bonfire. He was really gone, and in essence, my girlhood felt officially over.

We were able to move on, with new partners we love, and build families on opposite coasts. I have four sons, he has three sons, and we are blessed, I know. Often the demise of a monumental romance can keep you from growing and loving; you become stuck in what was, even if what was wasn't all that great. Bethesda psychologist Jim White calls this obsession the "what-if syndrome."

"It's an unrequited love, which the person did not have an opportunity to live out," White explains. "The person then goes through his life wondering, 'What would it have been like? Would it be better than what I have right now?'

"Of course, an unfulfilled fantasy is always more seductive than real life," he adds.

A hunger for advice on ways to exorcise festering fantasies has translated into packed shelves at bookstores of titles on how to let go, get over it, love the one you're with--the one you share kids with, a bathroom, the grind of reality. Yet how-to books work best when applied to the workings of the brain, such as learning to change a tire, stencil walls, make lemon meringue.

No instruction manual can rejigger the intricate hard-wiring of the heart, where love lives, and often never dies. As White puts it: "There's only a first time once. And that first time is so powerful, it leaves a permanent mark on the memory."

Debbie Glasser, a Potomac mother of three teenagers, met her first-love freshman year of high school in Oak Park, Ill. She was a cheerleader, he was a football star. They went steady for a year and a half, spending every day after school together, and every Friday, Saturday and Sunday night.

"He was my first real kiss, and my first real everything else," Glasser says of the boy who abruptly broke up with her during her junior year, leaving her for another girl, an apple-cheeked soprano in the high school choir. Being abandoned at the age of 16 by a boy she loved fiercely was an emotional jolt Glasser still feels at 45.

"It was so painful that I never wanted to feel that same kind of love again," she says. "I started choosing my boyfriends for different reasons, such as being a nice person or being stable, rather than gravitating toward romances with magic."

Throughout her decade-long marriage that ended in divorce, and subsequent serious relationships, Glasser has been unable to shake the incandescent love she once felt. Several years back, she tracked down her high school prince to see if there was anything left between them.

"He had a long braided ponytail and was living on a farm raising goats," says Glasser, who is dressed in Versace. "Thank God I found out we had grown in separate ways."

Yet Glasser never threw out her crushed, dried corsages from homecoming and prom. She just looked at them the other day, fingering the petals tenderly with French-manicured nails, remembering each event as if it happened yesterday, not 30 years ago. "How could I get rid of these things?" she says in a whisper. "They make me feel happy that I once had that kind of intense love."

In 1956, at Walter Johnson High School in Bethesda, Dan Shaver met a young girl he calls "the love of my life" in English class. Shaver, now 57, mourned silently for Stacey for decades to come, after his family moved to New Jersey during their junior year.

He "thought about her every single day" during four years at Dickinson College and often throughout his 22-year marriage. "That didn't help matters in my marriage," he admits of a relationship that produced two children, now in their early thirties. Newly divorced and still stuck on Stacey, Shaver mustered up the courage to call her after 24 years. He was living in St. Louis, and she in Middleburg--divorced, single, no children. They agreed to meet for dinner in Washington, a long meal at the Jockey Club that led to other long meals and long weekends.

"When we started talking, right away it was very comfortable, very easy, like time had stood still," says Shaver. "In my gut, I knew that Stacey and I belonged together the whole time we were not together."

They married in September of 1986, overlooking the 18th hole at Pebble Beach.

During their years apart, Stacey Shaver, 58, also sensed an intuitive rightness about the boy with the flat-top buzz cut she loved at first sight.

"I was devastated when he moved away in high school. We were madly in love. When he called me out of the blue and announced, 'This is a voice from your past,' I said, shaking, 'Dannnnny?' I was so excited. I never thought I would see him again. But on another level, I always knew we were meant to be together."

Maud Lavin and Locke Bowman, girlfriend and boyfriend during three years at Harvard in the early '70s, fell back in love in their forties after an urgent and erotic reunion in cyberspace. He was a divorced lawyer with two sons living in Chicago; she was a divorced writer with no children living in New York. A friend put them back in touch and they decided to have dinner, their first date in 22 years. Awash with sexy memories, they began courting through e-mail--hot, bold, tender dispatches, amplified by electronics.

Here's a snippet of how their e-mail correspondence "avalanched," in their words, into falling in love again.

To Locke, from Maud: "What I'd really like is just to see you again . . . talk a lot, joke around, flirt, not jump into bed (sorry), have a good time. (Well, I would like to jump into bed, and I'm very sure it would be wonderful, but not out of the blue, not quickly, not torn from what could be a luxurious and sensual series . . . )"

To Maud, from Locke: "Does this happen to you a lot? Getting into this kind of an e-mail relationship? I want to see your face and taste your mouth . . . and know you again. I want it to last forever."

To Locke, from Maud: "I want to love and be loved. I want passion, and I want cuddling and tenderness. I eventually want . . . to remarry . . . After finally feeling deeply again, I don't want to put myself on hold in a long-distance, yearning, can't-have-him mode. I decided to take the risk and tell you what I'm feeling."

To Maud, from Locke: "I'm rushing this out just to say that I have been feeling all the things you were describing in your e-mail and I lie awake at night and think about you."

Maud Lavin and Locke Bowman were married April 16, 1997, in Chicago's City Hall. Reflecting on their second chance at romance and commitment, Lavin has this to say: "To be in love as kids, then again as adults, it's very heady. There's a lot of warmth, a lot of humor, a lot of loyalty, a lot of respect for each other on how far we've come. That person knows exactly who you are."

I ask Lavin if being in love with someone at 44 whom she loved at 19 makes her feel like a perpetual teenager.

"In a way, the eroticism and playfulness make you feel young, but we're very aware that we are middle-aged now," she says. "I do not feel like a teenager, but I do feel lucky. It's very nice to grow old with the person who was your first, big love."