As the old Yiddish proverb goes: Man plans and God laughs.

And man, did I plan. There are few careers that require as much planning as a career in medicine. The process is enough to encompass the life of one person; add another to the mix, and the planning becomes all-consuming.

Jarrett and I met as pre-med freshmen in chemistry lab and became fast friends, laughing over the flame of a Bunsen burner as we set up experiments. We were soon inseparable, playing endless games of Dr. Mario on my Nintendo between study sessions. Sometimes, after a night of fraternity hazing, he would come to my dorm room and profess his love for me. I initially laughed it off, reminding him that he was my best friend. But by the spring of freshman year, our relationship had changed. We felt that we were beshert — meant to be. Driven by love and mutual goals, we started planning.

We managed to get into residency programs in the same city and moved from New York to Chicago, two newly crowned M.D.’s flush with excitement from the perfectly executed wedding that had sent us off.

But working a combined 160 hours per week was tough on our marriage. My once cheerful, thoughtful husband was becoming increasingly moody and distant. I confronted him: Was he having an affair? No! Did he not love me anymore? No. Was he gay? Silence.

“I think I might be,” he said.

With those words, everything changed. We stayed up for nights on end, talking in circles. We withdrew into our own world, me retreating into the closet along with him. “We love each other, we can fix this,” we told ourselves. But it eventually became clear that this was not a “fixable” problem. I gradually confided in my family and friends, putting aside my own reluctance to “out” him; Jarrett came to do the same, finally accepting this long-hidden part of himself. He moved out and we finished the latter half of our residencies newly single, plunging into the world of online dating, both in the market for thirtysomething men.

I learned to live without him. I “matched” again, and planned to move on in Philadelphia — a new start.

The next hiccup in my plans was a cough. At first, it was mostly after my near-daily four-mile run, but soon it was constant. At the time, I was reading “When Breath Becomes Air” by Dr. Paul Kalanithi, a neurosurgery resident who learned he had stage IV lung cancer at age 36. I had a fleeting moment of panic, and I shared my fear with a co-resident who was reading the same book. She confessed similar thoughts, and we reassured each other — of course neither of us had lung cancer. It was winter; we worked in a hospital; everyone was coughing.

I was still wearing hospital scrubs when I went to get a chest X-ray.

Maybe that’s why the technician spoke to me in an unusually direct way: “I’m no radiologist, but there is definitely something there.”

Despite our best plans to “start over” after our divorce, Jarrett and I had both ended up in Philadelphia for our fellowships. I had seen him only once since the move, when our eyes had met across the sweaty room of a spin studio. I had resolutely decided not to interact with him any more than was necessary.

It now seemed necessary. I knew very few people in my new city. It suddenly seemed beshert that my ex lived and worked right next door. Jarrett was the first person I called from the doctor’s office and there he was, immediately by my side to resume his abandoned duties as my best friend.

I spent the following days in the hospital, my family now beside me, balancing on a wobbly tightrope that separated me as a doctor from me as a patient. My medical team would come in and relay information in the complicated jargon that is often more familiar to me than lay English. I found myself translating everything back to my terrified parents, as if they were my patients and I was trying to soften the blow of bad news.

“Right inferior mediastinal mass encasing and occluding the right inferior pulmonary vein” became “I have something that looks like a tumor in the middle of my chest.” “Favored to represent lymphoma” became, “I probably have a type of blood cancer, but I can get through that.” “Other unusual primary lung malignancies can occur in a patient of this age, but are considered much less likely” became “don’t worry, I don’t have lung cancer.”

The morning the oncologist came in to my hospital room and told me that I had lung cancer, I had just been laughing with my parents. It’s not that I was expecting good news, I wasn’t. But I was just as unprepared to hear “lung cancer” as I had been to hear Jarrett say “I’m gay.”

I felt myself begin to tip from my tightrope and tried to grab back on, terrified to begin the long descent toward the “patient” side. As I wavered, I could hear my mother in the background trying to assure me that “we’d get through it.” The oncologist, her voice cracking, explained to my parents in plain English that some cancers are not curable. Mine is stage IV.

I still tried to translate, but this time I could barely get the words out. “That means that I am not going to live a long life.”

As a physician, I have been trained to be observant, to pick up on subtle clues. I sometimes think that I was so determined to stick to my plan that I neglected to see what was right in front of me. But then I consider that many men like flowers and it does not mean that they are gay, and many 32-year-olds get a cough in the winter and they do not have lung cancer.

I have now been living with cancer for a year. Treatment has, at times, left me feeling sicker than I could have ever imagined. I have felt deeply angry, profoundly sad and all-around terrified.

But for the first time, I am also learning to enjoy the here and now instead of focusing on the later. I might never see the finish line of fellowship graduation, but I am still a doctor; I am lucky enough to be learning every day and can still make my own patients’ lives better. My years of education and training have allowed me to build a supportive community of friends and colleagues throughout the country. I have a family who has stayed by me through all of it.

And, for better or worse, I have a gay ex-husband who is here for me, always.