“I see this super-tall guy get in our [van], and I was like, ‘Oh my God, Jill. Tell me what’s wrong. Do I have another stalker? Why is Rome sending personal security with me. . . . And she’s like, ‘No, that’s Alexis.’ I remembered his name because it was a unique name. I was like, ‘Oh, I remember.’ ”

After recognizing him, she invited Alexis to join her team for dinner that night. It didn’t work out. But something was in the air, and as our love story continues, there’s only one place to find out just what.

After Serena won the Australian Open, the next big tournament was the second leg of the grand-slam circuit, the French Open, at Roland-Garros, later that month. She texted Alexis that she was bummed that he had not seen her play well in Rome and proposed that maybe he should come to Paris. To Alexis, it was one of those classically inverse L.A.-style invites that are extended because you are sure it will never happen.

But Alexis did come to Paris for the weekend. Not that he had any particular expectations. “Even if she blows me off and we don’t even hang out, I’m still going to have an amazing time in Paris, and I’ll have an even better story for all my childhood friends when I was like, ‘Yeah, I went to Paris for a weekend. I was supposed to meet up with Serena Williams, she blew me off, but I’ve got other friends there, and we had a great time.’ ”

The tournament, which Serena would ultimately win, had not started yet. So Alexis and Serena got into an Uber near Serena’s apartment and drove toward the Eiffel Tower. They stopped at a zoo Serena knew about called La Ménagerie in the Jardin des Plantes, then at a stall selling candies. Serena became excited, like a small child, and Alexis bought her some.

They just walked and roamed, Serena placing her faith in Alexis because he was a tried-and-true traveler, where all you needed was a backpack and the only rules were none. Alexis also sensed that this was not something Serena ever got to do as a worldwide celebrity, so much of her life being about regimen and glamorous scenes where acolytes circled like fireflies. For six hours they walked all over, the magic of the day multiplied by the city’s heartbreak of beauty, which only made it more beautiful.

April 2016

The day of his birthday, April 24, Alexis went to the Carousel Restaurant in Little Armenia in Los Angeles with his grandparents. Serena and he FaceTimed. She was calling to say happy birthday, which might not sound like a big deal but was because she is a Jehovah’s Witness and part of the religion is not to celebrate birthdays. She was doing something she normally would not do, reaching beyond, telling him on the phone how wonderful their lives together had been.

Alexis knew then he wanted to marry her, not simply out of happiness or compatibility. She was helping him become the best version of himself because of her own work ethic and focus, with millions watching and the expectation of the public that she should win every time, what Serena herself described as carrying “three pyramids” on her shoulder. He thought he worked hard—it is part of the romance of high tech that everyone works 18 hours a day and then curls up under the desk for a few hours’ sleep with their laptop as teddy bear and pacifier—but he realized it was nothing compared with Serena.

“I felt like a door had been opened to a person who made me want to be my best self. . . . I find myself just wanting to be better by simply being around her because of the standard she holds.”

December 2016

Alexis decided he would surprise Serena by proposing to her on December 10 in virtually the same spot he had first met her: the Cavalieri. It was an intricate and tactical plan, several months in the making. Serena was scheduled to play in an exhibition in India, so Jill Smoller talked her into making a stopover on the way back and spending the night at the Cavalieri. Then the exhibition was canceled. There was no reason for Serena to go to Italy. Plus, she was beginning training for the Australian Open, and when Serena gets close to a grand-slam event, practice becomes a personal Hacksaw Ridge—fury, broken rackets, sometimes tears. Now going to Rome?