It is unusual, doctors tell me, for a woman to become psychotic for the first time at age 50. Rarer still, I had no family history of serious mental illness.

I was three years divorced, living in leafy, small-town New Jersey, when I looked out my kitchen window and saw a neighbor friend drop off some wildflowers he promised for my nascent woodland garden. He didn’t ring the bell. It was hot outside, so he placed them under the shade of a crape myrtle.

As he pulled away, I felt, to my great surprise, maybe a half dozen little orgasms ripple through me.

From that moment, I had touch-free orgasms whenever I saw him or heard his name. Suddenly, this man’s physical beauty was unparalleled. He was a creative genius. As I slid into an 11-year delusion that overtook my life, he became “my beloved.”

I found myself mind-melding with him. By that I mean I could have whole conversations with him without needing his physical presence.

Soon I realized my beloved and I were the main characters in an odyssey that involved Russian spies, NASA, a citizen militia and 17 United States intelligence agencies. The fate of mankind rested on humble me. And on my beloved. The hardest part was that I could reveal none of this to anyone. To do so would imperil our lives.

I can’t remember exactly when I began slipping into my own personal Narnia. One night I was snuggled under my comforter, flipping through Emily Dickinson poetry, when the line “Tell all the truth but tell it slant” winked at me, lifted itself off the page, turned at an angle, then righted.

A fresh mind-meld flashed. Of course! To avoid detection, the supersecret spy language was one of oblique associations. Events, people and objects all interlocked. A world that looked ordinary to others was drenched in meaning for me.

When reading a scientific article for work, I would see certain words lift off the page, hover like a hologram and self-assemble into a passion poem for my beloved.

In one mind-meld, my beloved said he would meet me that night. In anticipation, I lined my bedroom with candles, started a blazing fire, dressed in stilettos and a fur-lined leather coat (over my lace negligee), then lounged on my bed drinking scotch.

Midnight became 3 a.m. As the fire went cold, I sent a naughty email from a fake account (so raunchy, I blush to remember it) and then fell asleep, candles still burning.

I woke early, hung over, out of coffee, and furious with him for standing me up. As I drove off to get my caffeine fix, guess who I saw — my beloved! He was walking his dog. I pulled up next to him, lowered the window and glared.

He bent down. “Is something wrong?”

I shot him a look of icy disdain, then peeled out with a screech.

Headquarters insisted I see him as much as possible, so I volunteered where he volunteered, showed up at events where I knew he would be, scoured the internet for mentions of his name.

I was able to work my public relations job for four and a half years and keep up with the delusion. But the delusion gods wanted me to go regularly to the psych ward, where I was loaded up with antipsychotics, zapped with electroconvulsive therapy, and where my diagnosis deteriorated from bipolar I (the manic kind) to schizoaffective disorder (halfway to schizophrenia). I had no choice but to go on disability.

My irritation mounted each year. It was like being caught in a whirlpool, the same information going round and round. My beloved seemed clueless. He knew nothing of NASA’s plan to cryogenically freeze our bodies and launch us to a faraway galaxy. Was headquarters simply incompetent? Why was I getting mind-melds to propose if he was just going to turn me down?

I needed less noise, more signal. Headquarters was always putting my beloved’s needs first, sending me vexing mind-melds that he needed to move into my house and have his own bedroom suite.

How? Who would pay for the renovations? I felt like a querulous housewife. The honeymoon was long over and so were the big Os.

At headquarters’ insistence, I proposed marriage, twice — the first via email, and the second, a half dozen years later, in person. I asked him for a ride home following a nature hike, and when we pulled into my driveway, I said, “So, have you had time to think over my marriage proposal?” I was trying to be funny (six years later!) to give myself emotional camouflage should he decline.

He scrunched his brow. “Are your children still living with you?”

After an awkward silence, I said goodbye and hopped out.

At the time, I took his question to mean he wanted to make sure I had enough room for him to move in. Later, I relayed this scene to a friend with whom I would hold countless post-delusion post-mortems. I would interpret signs one way, and she would sigh and set me straight.

“He probably thought you were acting strange,” she said, “and was wondering if your children should take you to the hospital.”

My sanity returned slowly, like an incoming tide, then all at once, like a thunderclap. What a relief it was to no longer be burdened with saving the world. Truly.

Why did it suddenly end? The doctors claimed it was medication finally kicking in (I had been noncompliant sometimes in the past). But delusion disorder is often difficult to treat with medication alone. I think I just got so frustrated at headquarters that I finally resigned my position as martyr in chief.

When the delusion ended, my diagnosis of schizoaffective disorder remained. After a long blackout of weeks (or months), my faculties returned. But I felt a thick viscous membrane between others and me. Now came the hard work of reconnecting with the outside world, or as a friend says, with consensual reality.

It wasn’t hard to let go of the aliens, the Russians, the intelligence agencies. Though they had lived in my head for 11 years, all that was obviously, suddenly, nonsense. I evicted the big delusion easily, but the little delusion — that of my beloved — persisted. He was a deep groove in my psyche.

Intellectually, I understood that my love for him was inauthentic, yet it felt deeper and more real than any romantic love I had ever known. It didn’t help that all those orgasms likely spilled oceans of oxytocin, the “love hormone” that creates feelings of closeness and belonging.

I decided to take a systematic approach to extirpating him from my heart.

I experimented with exposure therapy, the same way you might force yourself to look through a herpetology book to combat a snake phobia. Not surprisingly, this only intensified my obsession.

Next, I treated him as an addiction and stayed away. Then, in a small notebook, I wrote the names of everyone who had ever been a positive force in my life — my family, kindergarten teacher, best girlfriends — and touched it every time I thought of my (former) beloved, whose name was not inscribed.

These are real people, real relationships, I told myself. Not imaginary playmates.

Slowly, the beloved eased out of my heart, leaving behind only a splinter of grief.

How to make sense of the past 11 years? “An attitude of gratitude will be helpful,” said my therapist. It was hard to feel gratitude. What I felt was a hot poker of shame jabbed into my gut. Who was that lady shouting gibberish and thrusting her umbrella into the sky in front of her beloved’s house? That was not me pretending to be crazy. That was me being crazy.

And what about those eight hospitalizations? Was I grateful for those? No.

My new therapist says it’s OK not to feel 100 percent gratitude. I don’t. But I am profoundly grateful to have rediscovered real love — that of my children, siblings, close friends. They could have forsaken me but instead stayed the course.

A while ago, I drove past my former beloved on his bike. He had stopped to look at a leaf on a tree branch. He was wearing a bike helmet, his now-gray locks licking out from underneath. He looked angelic, like a child. Each day of those 11 years, I anticipated him loping up my driveway and ringing my bell, his arrival signaling the end of the mission, his profession of love to me the ultimate reward for all I had sacrificed.

I finally understood with exacting clarity that he was not part of me, that his soul was not entwined with mine. He was just a man. On a bike. Riding down the street. In the opposite direction of my house.

Teresa Riordan is a writer in New Jersey.

Modern Love can be reached at modernlove@nytimes.com.

To find previous Modern Love essays, Tiny Love Stories and podcast episodes, visit our archive.

Want more from Modern Love? Watch the TV series; sign up for the newsletter; or listen to the podcast on iTunes, Spotify or Google Play. We also have swag at the NYT Store and two books, “Modern Love: True Stories of Love, Loss, and Redemption” and “Tiny Love Stories: True Tales of Love in 100 Words or Less.”