For nearly three years now, my brother in law has led a double identity.

Two women. Two lives. One illicit child.

One big secret.

It troubles him. He thinks about it each day he awakens at his sprawling home 10 miles north of the city’s teeming public squares, ancient dynastic buildings and foreign embassies, in an exclusive community not far from the Capital Airport. His recent business ventures have concentrated on a mining project in isolated Xinjiang province and he shuttles to and from the far-northwest region, now troubled by a growing Muslim insurgency driven by indigenous Uighurs.

It’s a low-level war aimed at driving out the influence of the invading ethnic Han who in recent years, at Beijing’s direction, have colonized the region with settlers and outside investments. From entrepreneurs like Xie Yi.

While in Beijing, he answers the phone with the typical Mandarin salutation, but in his low husky voice, the phrase seems barked, like a command.

“Wai!” Hello!

The male voices on the far end of the line offer progress reports, with Xie Yi listening intently, driving in his black Mercedes S600 or leaning back on the living room couch, smoking cigarettes with a wooden filter tip, like The Penguin character in the old Batman TV series.

“Due, due, due,” yes, yes, yes, he purrs before breaking into a soft laughter. Perhaps his associate is telling of a new girlfriend, a local woman taken on just for the length of the project, or some other private joke. The calls are all business; or almost.

Xie Yi is a creature of the night. He stays up until dawn most days, sleeping until well past noon. His earlier years were spent roving the city — to little-known street eateries, bars, clubs, upstart restaurants popular among natives in the know. In an exploding Beijing, with its unleashed commercial energy, there was always someplace new to go. When he didn’t go out, he spent the small hours in his office, in front of a computer screen, researching new business ventures; his ash tray overflowing with spent butts.

Back then, gambling was usually key to most nights. He’d play cutthroat games of mah-jong for high stakes with an exclusive cadre of friends wealthy enough for admission to the table. He traveled in a posse, usually, this friend or that. But there was one person always by his side: his girlfriend Liu Ning.

They met as teenagers: she one of many girls who were attracted to Xie Yi’s brooding good looks and self-confidence. She was persistent. And she won. There’s an early picture of Liu Ning taken from those days. She’s on the telephone; the picture snapped just as she realizes the camera is pointing at her: she’s young, lively, lovely. Her eyes are soft.

They became an instant team. Not only was Liu Ning pretty, she was also smart. She had street sense and quickly became equal partner to Xie Yi’s growing business ventures. She had a knack for finding contacts in all walks of Chinese life. She did favors for people, and they responded with typical Chinese guanxi — one hand washing the other.

When we visited China, Liu Ning was always there to greet us with free coupons to exclusive spas, restaurants. She could get me boxed DVD sets of my favorite TV series. For awhile, while the connection lasted, her contacts at Capital Airport allowed us to fly business class on flights leaving Beijing, no matter the airline. When a friend brought a dog into the country, the animal avoided the timely and costly quarantine at the airport and was released within hours; Liu Ning at work again.

As the years passed, the business grew, but not so the relation between Xie Yi and Liu Ning. Living the good life in a country where so many got by on so little, she gained weight. At times, their relations seemed strained. Xie Yi would shout at her over seemingly little things. The family met on several of our visits: The decision was that after so many years, Xie Yi should marry Liu Ning, make her an honest Chinese woman. He refused to even discuss it.

But she would not give up. She fed him in bed each morning, and was constantly at his side. If Xie Yi went someplace, she went as well. Ma jong games. Business trips. Errands. Haircuts. She shared his every opinion, on any topic.

I joked that she was more than his girlfriend; she was his “jing cha,” or policeman; always there, always vigilant, keeping him in her sights. He’d laugh.

“Mei ban fa,” what was to be done?

There were illicit affairs; nothing serious. Xie Yi once started seeing a young woman, a trainer at the gym where he went to swim. One day, Liu Ning was running errands with an employee and saw Xie Yi’s car parked on a nearby street. He was inside, having a private talk with his paramour.

She called his cell phone.

“Where are you,” she said.

“At the gym.”

“Then why is your car parked on the street? I can see you.”

He was busted, and it enraged him. He brought the woman home. Told Liu Ning that she was his trainer, and that if she wanted to do anything about it, she could leave. He told her she could take half of everything they owned, no questions asked.

It was time to part ways. She refused.

But a mah-jong game changed everything. Xie Yi often hosted these faceoffs that attracted a changing lineup of players, including women. Liu Ning never played, but she was there by his side, with a silent jealousy of any competitor with the slightest designs on her man.

Once, a tall woman and her friend showed up. I don’t know how they heard of the game, but the tall one became a regular. Large-boned, she wasn’t a beauty, but she met one of Xie Yi fantasies: she was tall.

He was instantly attracted to her. And they began an affair.

We would get snippets of the Beijing goings-on during our trips there. Then one day, word came to the U.S.: Xie Yi’s girlfriend was pregnant.

The family was livid. But Xie Yi again refused to back down. He wanted a son. And he believed that a tall woman would bring him a strong, tall, strapping boy. His parents closed the door: They loved their son but they also loved Liu Ning like a daughter in law. They didn’t want to know any more details.

The baby was born: a boy. Lui Ning was never told about anything.

Xie Yi rented an apartment for the new mother and her three nannies. We went for a visit one summer. Seeing the boy brought tears to my eyes. Large black eyes. Exotic. Innocent. Unknowing.

The mother was happy. Xie Yi told her that he loved her. Once, he went through her cell phone to see who she had called. He couldn’t always be there, and that fact bred a raging insecurity.

Suddenly, he was the suspicious jing-cha.

Every other day, Xie drove from his home to the nearby apartment where his new family lived. He told Liu Ning he was going to the gym. She never protested. Once, we accompanied him and leaving the flat, I turned to my brother in law.

“Xie Yi,” I said. “You are leading a secret life. Two lives at once. It must be a burden.”

He didn’t answer, didn’t offer any excuses or insights. He stared ahead into traffic.

Mei ban fa.

The new arrangement changed things at home. Xie Yi no longer shouted at Liu Ning; the tension of being a trapped man evaporated.

But at our recent trip to the spa, as we sat in the warm waters, Xie Yi wanted to talk about things: We knew there was bureaucratic trouble with the baby. Because the parents were not officially married, the child could not procure a hu-kou, or license. It was like being born in the U.S. without a social security number. The boy had no official identity.

His parents were working on the problem, looking into an underground deal, but rates were sky-high. Some black market hu-kou went for $100,000 or more. That was a lot of money to spirit from his live-in business partner, even for Xie Yi. Meanwhile, they planned to put the child into a foreign-run school where such documents weren’t necessary.

The girlfriend wanted her baby and she wanted Xie Yi. But she was practical. She suggested that they all live together in one household, Liu Ning included.

“Utah,” Xie Yi said to me, the word suggesting the once widespread Mormon practice of polygamy.

And there was more: the girlfriend wanted another child.

I knew how my wife’s family felt about that, and I tried to tell Xie Yi in my limited Mandarin.

What came out is this: One secret is enough; two far too many.

He understood. And he knew he could on me for an unjudgmental ear.

He knew my history of being selfish with women. Decades ago, before I met his sister, my first wife had become pregnant. But I was too absorbed in my own career and self-identity as wanna-be hipster to make room for any child.

She had an abortion and immediately fell out of love with me.

He said his partner wasn’t yet pregnant, his voice trailing off. Then he mentioned it: Maybe his son could come live with us, in the U.S.

Lily had mentioned this before. The sisters wanted their nephew to have every advantage of life in America. The strange relationship that brought him into the world certainly was not his fault.

My wife’s plan was simple: I could retire from my newspaper job and raise the boy, while she continued to work to pay the bills. I could even write a book about the experience, if I wanted: Childless American writer raises Chinese boy.

I said I’d think about it.

But this was the first time I ever heard Xie Yi mention such an arrangement. A few days before, we met the new family at a Starbucks. We had some baby formula brought from the U.S. to give the new mother. The boys was nearly two now. The excess nannies had been let go; there was only one now.

I asked the mother if she would ever want her son to go the U.S. She looked doubtful. She wanted both of them; both of her men. I knew instantly she would never let this happen.

I told Xie Yie this, but he just smiled.

In China, the shared-raising of children is a longstanding tradition. When my wife’s younger sister was small, her parents sent her to live for a time with her grandfather, who had taken the astounding step of divorcing his wife and marrying a younger one. The family was scandalized. His daughter, my wife’s mother, thought having a child around would help things.

Lily never wanted to have children, so that was that. “Why have kids when you can sleep until noon?” she always said.

Xie Yi has met my younger brother Frank and his three children.

“Why can’t Frank give you one of his children?” he asked.

The question was serious.

“That’s not how we do things in America,” I told him. “They’re Frank’s kids.”

He grunted and stared into the water.

Mei ban fa.