The U.S. Customs officer eyed Sang's well-traveled South Korean passport. "What is your purpose in the United States?" she asked. Sang said he was "on holiday" and would be going back to Korea in two weeks, yet agents still pulled him aside from the rest of the arrivals at Chicago's O'Hare International Airport last November. Bogged down with suitcases and jet lag, they filed into two lines, one for citizens and residents, one for foreigners — the chasm between "Welcome home" and "How long are you planning to stay?"

Sang's passport had five United States stamps in it from the last three years, and the airport interaction had become routine. Sang would say he was on holiday, the officer would give him three to six months, and that would be that. This time, however, he was led into a room with other travelers singled out for further interrogation, and, as two hours ticked by, Sang contemplated what he'd say.

Would he tell the truth? That his life forever changed when he chatted up Mark D., a vacationing San Francisco bank executive, outside a restaurant in his native Seoul three years back? The encounter kicked off a series of trips between South Korea and San Francisco, chronicled in the photo albums Mark custom-designed online, each printed in a hardback book with its own message on the back cover: "It took 39 years to find you and now that I have, I will do everything and anything I can to make you smile everyday." The photos show Mark (a graying ringer for Supervisor Bevan Dufty when wearing sunglasses) next to a buff Korean who could pass for 15 years Mark's junior instead of three. You see them smile in Union Square. At a spa in Marin. At Caesar's Palace in Vegas.

In June 2008, they donned their best suits and married at San Francisco's City Hall, something unfathomable in Korea, where Sang's family still thought he was living in the United States with a woman.

So would Sang tell the immigration officer that Mark was back in their Richmond District apartment at that very moment, ready to pick him up at the airport for their latest spin around the leaving and re-entering carousel of the last two years?

No, telling the truth would be self-sabotage. So when the stern officer walked into the room and loosed a barrage of questions, Sang did the worst thing he could possibly do.

He lied.

"Are you married or are you single?"

"Single."

"According to our records and your crossings, you have spent 19 1/2 months in the United States out of the last 22 months, and less than three months outside of the United States, is that correct?"

"Yes."

"Why do you spend so much time in the United States?"

"Traveling."

"Where do you stay in the United States?"

"At my friend's place."

"What's your friend's name?"

"Mark D." (Mark's and Sang's names have been changed for this story.)

"Is Mark D. married?"

"No, he's not married."

Sang provided the officer with Mark's cell number, and the woman left the room.

She called Mark and continued the interrogation: Where does Sang stay? What does he do? Are you married? Mark said he was. He didn't think twice about answering truthfully. He thought they'd followed the law to the letter; Sang always left the country before the deadline Customs allotted him.

The officer hung up and returned to Sang. After more questions, she left the room a second time to call Mark.

"Sang says you're not married, so who's lying?" Mark recalls her asking.

Mark realized there was a big problem. Still, he saw it as a situation in which neither of the men was lying. "My marriage is not recognized by the federal government," he replied.

"Excuse me?"

"My marriage is not recognized by the government."

"Are you married to Sang?"

"Yes."

"That's all I needed to know," the officer said, hanging up and returning to the room where Sang was sitting with his nerves fraying.

Sang was trapped.

"Just a few minutes ago, I spoke with Mark and he admitted you were his husband. Is this correct?" the officer asked.

"Yes."

After Sang said he lied because he was scared, the agent revoked his tourist visa for misrepresenting himself to a federal immigration officer and for being an immigrant (which technically means someone intending to stay in the country) not in possession of an immigrant visa. To reapply for a visa in the future, he would have to apply for a waiver for fraud. What she didn't say is the only way to get a waiver is to prove his absence would cause "extreme hardship" for his spouse in this country — and, of course, in the eyes of the U.S. government, Sang does not have a spouse.

"Is there anyone you'd like to call?" she asked.

"Just Mark."

When Mark answered, Sang wept. He spent the night in a holding area and boarded a flight back to South Korea the next day.

U.S. immigration law prioritizes family unity. Marrying a citizen is still the most common way to get residency, and everyone knows there are more than a few scam marriages squeaking through. Yet for gays, it's a very different story. Since federal law only recognizes marriages between men and women, gay partners are left with no way to sponsor each other to stay in the country.

Now that Arizona's "papers please" law has pushed immigration reform to Washington's front burner, Democrats propose allowing "permanent partners" to be treated the same as spouses under immigration law. While 19 countries have similar policies, it won't be an easy sell: The gay lobby fears they'll be sacrificed as a bargaining chip to get Republicans on board, while pro-immigrant groups worry that adding in gays will ruin any chance for reform for everyone else.

While critics say letting permanent partners through the gate invites fraud — how do you validate the relationship without a marriage license? — others say the current system is what encourages people to cheat. So what do you do when the law won't permit you to be with the most meaningful person in your life?