Perhaps less inevitable was that the late authors' spouses would end up together, too.
"I'm still surprised," said Lucy Kalanithi of her relationship with Nina Riggs's widower, John Duberstein. "I'm surprised by how ridiculous it is and how natural it is at the same time."
Sitting across the kitchen table from Lucy last week at her home, John agreed. "Everything seemed almost bizarrely to fit," he said. "It was kind of stunning."
The story of Lucy Kalanithi and John Duberstein is both unlikely and destined, the stuff of a rom-com. It begins, tragically, on a deathbed.
In the final days of her life, Nina Riggs was worried about her husband and how he would get on with his life when she was gone. Nina made an offhand suggestion: Contact Lucy Kalanithi. She has experience with this, she told him; she'll know what to do.
At the time John had only a vague idea who Lucy was. He had yet to finish "When Breath Becomes Air."
Lucy and Nina, however, had formed a quiet relationship. Lucy, whose husband died in March 2015, had contacted Nina after reading a Modern Love column she had written for the New York Times, "When a Couch Is More Than a Couch." Lucy wrote a glowing blurb for "The Bright Hour" and stayed in touch with Nina's agent, inquiring about Nina's health and her family.
On Feb. 24, two days before Nina died, Lucy sent her an email message: "I'm beaming you love from my whole being." She signed it, "your forever fan, lucy."
At a hospice in Greensboro, N.C., John read the email to his ailing wife and responded on her behalf. "Thank you for being such a strong supporter and friend to her," he said. "She's talked about you a ton these past few weeks, and her sense of you being a person with great insight and empathy. She's clearly on the mark there."
One of Nina's final acts, in effect, was to play matchmaker for her husband.
John, a 41-year-old lawyer, was unmoored by his wife's death — bereft, sleep-deprived, fearful of his future. "I had so many questions," he said. "I was bursting with this intense need to get things squared."
So he did as his wife had suggested. His note to Lucy — two days after Nina died — was lengthy and, in Lucy's words, "obscenely vulnerable." His requests for advice were wide-ranging: How do I write a eulogy? How do I sleep through the night? How do I not go insane?
Lucy wrote back immediately, advising John to focus on the eulogy and "to take a chill pill" about the rest. "I felt a desire to support their family," she says. "And Nina was John's character reference."
John got through the eulogy. He got through the next day. But not without emailing Lucy. Over the next few weeks and months, she became his lifeline — and, in turn, he helped her realize that she had come a long way in the two years since her husband's death. "I felt like your guardian," she said. "You totally were," he said.
The emails grew in volume and intensity. "We learned that when a Gmail thread reaches 100, it rolls you into another thread," he said. There were spools and spools of threads, "a Google-plex" of messages, he joked.
Their feelings for one another grew and took on new shape. "We talked a lot about the minefield of managing to fall in love and actively grieve at the same time," she said.
There were also lighter, more flirtatious exchanges. They gossiped about the private Facebook group Hot Young Widows Club and shared poetry. He sent her Philip Larkin's "When First We Faced, and Touching Showed":
Behind the moonlight and the frost,
The excitement and the gratitude,
There stood how much our meeting owed
To other meetings, other loves.
The decades of a different life.
In late April, Lucy, who is 38 and a clinical assistant professor of medicine at Stanford, had a business trip to Raleigh, N.C., about an hour from John's home. "I knew I had to see her," he said. Lucy felt the same way.
At the time, the two had never spoken — they had made an email-only rule. Seeing each other face-to-face was intense. "We held each other a long time," she said. There were two dinner dates and, by both accounts, "a lot of chemistry." Kalanithi then returned to California.
Their relationship was blossoming but still mostly a secret. John's children — Freddy, 10, and Benny, 8 — knew about it, as did Lucy's 3-year-old daughter, Cady. Nina's publisher had arranged a dual publicity tour in June for John and Lucy — given the common theme of "When Breath Becomes Air" and "The Bright Hour." Lucy and John were both terrified and excited to be onstage together. At one engagement — a Facebook Live event in Sausalito — interviewer Kelly Corrigan jokingly asked when John and Lucy might get engaged. "John turned purple," Lucy recalled.
By the end of the summer, the couple had begun to speak openly about the relationship to their extended family and friends. There were sweet photos shared on Facebook. The families got together regularly — though the arrangements are difficult, with three children, two jobs and a continent between them.
As the kids played in the yard in California last week, John and Lucy bantered over which house is more child-friendly, which has more bedrooms, which climate is better. "We need to find a place in the middle and move there," Lucy said. They joked about writing a sequel to their late spouses' books: "When Breath Becomes the Bright Hour."
At Lucy's home, reminders of their late spouses remain. There are photos of Paul in the kitchen and along the hallway; on the refrigerator is a Christmas card of the Duberstein family, including Nina. In an odd coincidence, Lucy owns the same couch Nina featured in her column. Both John and Lucy still wear their wedding rings.
As the couple and their children celebrated the New Year's holiday together, there was a warmth and cohesiveness that made the group feel, as Cady says, like "a whole family." Duberstein sliced apples for Cady; the three kids drew and played games together.
In person and on the page, Nina and Paul had given their spouses "radical permission," Lucy Kalanithi said, to enter new relationships, even to remarry. But following through on that brings up complicated emotions.
"I planned to spend my entire life with Nina. I was 100 percent happy doing that," Duberstein said. Nina's death forced him onto another course. "Having a second relationship is a tragedy," he said. But he acknowledges with deep gratitude the series of fortunate events that have led him to Lucy — a woman his wife had tacitly approved.
Lucy and John both recognize the lingering pain and inevitable challenges they face. Entering into a relationship, Lucy noted, means accepting the possibility of losing your partner. "If you are lucky enough," she said, "you will be devastated when they die. Willingly entering that feels gutsy, but what else could you choose?"
For now, they are relishing their time together, in all its complexity. On Dec. 31, Lucy, John and the three kids headed out to visit Paul Kalanithi's grave, which overlooks the Pacific Ocean. They played Paul's favorite music and blew New Year's noisemakers. Together with members of Paul's extended family, they watched the last sunset of a sad, happy and surprising year.
Nora Krug is an editor and writer at Book World.