When Princess Martinez saw her husband for the first time after he was deported, two thoughts crossed her mind: that she loved this man, and that she might have to leave him.

The only other option appeared to be moving with their six daughters — who, like Martinez, are all U.S. citizens — across the border to her husband’s new home in Mexico, with its mounting violence and troubled schools.

“Everyone is coming to America, to the land of opportunity,” Martinez, 31, recalled thinking. “And here I am, thinking about taking my family in the opposite direction.”

There are more mixed-status families living in the United States than ever before — non-citizens and citizens under the same roof. Many of those families will be affected by the Obama administration’s aggressive deportation plans, with a record 400,000 immigrants expected to be returned to their home countries this year. It’s likely that more than 20,000 of those deportees have children who are U.S. citizens, according to experts who have analyzed federal data.

Parents are left to choose between dividing the family between two countries, to keep children who are U.S. citizens in U.S. schools, or moving together to Mexico or Central America, where the education is inferior and the language is often foreign to U.S.-born children.

But in the border region, there’s a third option, little known elsewhere, and now facing mounting opposition: living in Mexico but crossing the border each day for American schooling.

As the immigration debate has intensified and school budgets have tightened, some districts have sent photographers to the border to identify students crossing from Mexico. In Arizona, officials last year sued a district for not adequately vetting the residency of students.

Problems began for Martinez and her family when her husband, Marcos Perdomo, 34, was arrested for drunken driving in 2009. After a four-month prison sentence, he was deported to Mexico. On the day the family was reunited here in this border city, Martinez said she watched him scoop up their six daughters one at a time, letting them cry on his shoulder before wiping away his tears.

Martinez and Perdomo mulled their dilemma for days. Friends and relatives told Martinez she would be crazy to willingly move her family to Mexico, where violence was spreading amid an intensifying drug war. Perdomo said he didn’t know what he would do without the girls, now ages 4 through 13. Two of them had been diagnosed with learning disabilities — something U.S. schools, which on average spend five times as much as Mexican ones, typically manage better.

Martinez finally decided to move the family to Matamoros in early 2010 and make the daily journey across the Rio Grande with her daughters so that they could remain in the sleepy Texas school district of Port Isabel, where Martinez worked as a cashier at a grocery store. To evade residency requirements, Martinez registered her daughters for school using a relative’s address.

For months, the strategy appeared to be working.

No easy compromises

Martinez and Perdomo had met 15 years earlier at a Tex-Mex concert just north of the Rio Grande. Perdomo was a short, sturdy teenager then, a man Martinez’s family respected. They danced as accordions blared. He held her close, falling instantly for her smile.

That she was a U.S. citizen and he wasn’t meant little that night. And it meant little for much of their marriage. Perdomo had no problem getting construction jobs and paying rent on a little house in Port Isabel, where Martinez gave birth to six girls in 10 years. At school, each of them pledged allegiance to American and Texas flags.

After the move to Mexico, Martinez got accustomed to rousing the girls at 4:30 a.m. from the living room floor, where they slept shoulder to shoulder.

One winter morning, she tucked seven U.S. birth certificates into a handbag as she neared the crossing. Her six girls swarmed around her — pony tails and backpacks illuminated by the lights of the international bridge to Brownsville — slowing as they approached a U.S. customs agent.

Nearly all the agents recognized them — a blast of energy in this dreary checkpoint, with its waiting rooms full of tired men. “Did you bring your homework?” some agents asked. The girls nodded in unison.

Behind them were dozens of students who made the same journey to attend public schools in Texas. Many left behind parents like Perdomo, who watched his wife and daughters disappear over the Rio Grande — the beginning of their 15-hour day — through the windshield of his pickup.

“I was convicted, but the girls are serving the sentence,” Perdomo said.

The routine lasted for about a year. Then, in February, the superintendent called Martinez into her office. The district had learned of her daily cross-border journey.

“I pointed out to her how that was not permissible. And that we were in a position that we had to adhere to the law,’’ Port Isabel Superintendent Estella Pineda said. “I explained to her that she needed to make a choice.’’

This time there was no easy compromise for Martinez. If she wanted her daughters to attend U.S. schools, the girls would have to leave their father and move to the United States full time.

The girls complained. “Why can’t we stay here? Why do we have to move?” Brigette, 10, asked her mother over and over again.

“We’re still trying to figure it out,” Martinez responded each time. But she didn’t see any way around the move.

Amid another round of chastisements from friends and family, Martinez decided in February to stay in Mexico with her husband. Their daughters would move to Texas with an aunt and grandmother, returning only on weekends.

At their new home in Port Isabel, the girls spread their homework on a kitchen table, sounding out words and polishing basic arithmetic. Their aunt, Ida Martinez, darted between them to help, the way their mother once did.

Officials at the school district, with just 2,500 students, were by now familiar with Martinez’s saga and were glad to hear the girls had moved back across the border. But some thought their mother should be in Port Isabel, too.

“She should make the choice to stay here full time,’’ said Nancy Gonzalez, the principal of Garriga Elementary, which two of the girls attend. “The girls need her. Her children need her. And she needs to see that.’’

But three months after Martinez made the change, she still sees no other viable options, even though the current arrangement hardly feels sustainable.

The house is too quiet when she returns home now, she says. Sometimes she listens to the television’s soft chatter, half-expecting the interruption of a little girl’s voice. But there’s nothing.

Normally well behaved, the girls are getting in trouble in school. In Mexico, Perdomo is struggling to find a job in a city awash with drug-related violence.

Martinez crosses the border each morning by herself now, still working at the same grocery store, still trying to craft a plan that won’t make her feel like a failed mother or wife. She never comes up with one.

“If only I was smarter,” she said.

But that sentiment is quickly overwhelmed by anger — at her husband for committing the crime that led to his deportation, at the school district for threatening to expel her daughters, at a system that punishes immigrants without considering the impact on young U.S. citizens.

“Every time we think we’ve figured things out, there’s another setback,” Martinez said. “Something else happens, and we have to start all over again.”

Staff photographer Alexandra Garcia contributed to this report.