When Mary Ann Rollins was deployed to Afghanistan with the Utah National Guard, she was prepared for bullets, bombs, danger and even death – but not love.

During the months spent on tiny bases in the forested and often deadly mountains of eastern Afghanistan, she became close friends with Zia, an Afghan interpreter who regularly put himself in harm's way to save others, who always had time for local children and a kind word for anyone who was down.

Rollins' tour ended in 2009, but her close friendship with Zia continued over Skype and email – and grew into something more. Two years after leaving Afghanistan in uniform she was back as a civilian to get married.

"I wasn't looking for romance at the time at all, it just never crossed my mind," the 33-year-old told the Guardian from her home in the US. "When he told me he loved me I was surprised, but I realised that I loved him too.

"There's something about all of this that is almost magical. It's like it was meant to happen. It's amazing that I could find the person who is perfect for me, on the other side of the world, on a tiny outpost in a remote area of Afghanistan."

The wedding was low key, the honeymoon just a couple of days in Kabul, but Rollins had time to meet her new in-laws and get to know the chaotic, lively Afghan capital few foreigners ever see.

She returned to the US pregnant and armed with a sheaf of papers for her husband's visa application. She knew it would probably take months but had no idea the secretive, byzantine process would leave her stranded on opposite sides of the world from her husband for more than two years.

Now 15 months old, her son, Ryhan, shouts "dad" when his mum opens up her computer, in anticipation of one of the Skype chats that are their only contact with Zia, 30.

"I wasn't happy about not having my husband here for the birth, but I didn't expect that he would miss the whole first year of our son's life," said Rollins. "I'm glad that [Ryhan] does at least recognise his dad."

Zia – whose name has been changed to protect his identity – still works on a US base as an interpreter. Yet a decade of loyal service has done nothing to speed up his immigration case. The torturous limbo in which he, Rollins and Ryhan find themselves goes by the Orwellian name of administrative processing.

After usual visa checks are finished, some people need to supply extra information to get a visa, the US state department says. But applicants get no news on what is being checked – or how long it will take. Some have waited months, or like Rollins and Zia, much longer.

A state department spokesperson refused to comment on their case, but said "many factors can trigger the need for additional steps" in the visa process.

Rollins' local senator, Orrin Hatch, has asked about the delays on her behalf, and she has started an online petition calling on the US government to finish processing her husband's visa. More than 13,000 people have signed the e-petition so far.

There has been no response from Washington, but the publicity campaign did at least bring a message from someone who found themselves in a similar position.

Danielle Bennett had been deployed to Kandahar province with the Alpha Company of the 431st Civil Affairs Battalion.

Tasked with helping local women sort through compensation claims for damage from fighting, and handling supplies, she volunteered at a makeshift school, but also found herself spending more and more time with one of the Afghan translators, Karim.

"He really became my best friend," said Bennett, 26, who now lives in Arkansas. "He's so modest and humble, he's a really generous person."

The couple became engaged two years ago, after an informal commitment ceremony with friends on the base where they worked. The couple began Karim's visa application around the same time. They are still waiting for it to come through.

Karim, 23, agreed to speak to the Guardian, using only part of his name for safety reasons. He is now a student in Kabul, but remembers a lonely arrival on the US base in Zhari, a dangerous district where the Taliban leader Mullah Omar was born and in which heavy fighting continues.

He was pushed into the job while halfway through a college degree, because his father had to stop work and there was no one else to support their family. "I was a man who had spent most of his time at home, just going to school and back again," he said.

On the base, he had little company – until he met Bennett. Americans distrusted him for being Afghan and the local Afghan community condemned him for working with the Americans, Karim said.

"In a situation where nobody trusts you, and you are so alone, there is one person who trusts you and she is also beautiful, it's something natural," he said of their romance.

The couple's relationship won acceptance from both his family and her fellow soldiers. "A lot of the soldiers really cared about our situation," said Bennett. "Two years after I came back [to the US] we still get messages from our commander and other soldiers asking, 'How is [Karim], is he here yet?'"

Bennett added: "There was just one very odd moment when an officer I had deployed with called me to his office and said: 'This will never work out, what do you think you are doing.' All I could think of to say to him was 'I love him [Karim], we love each other.'"

Karim was approved for a visa online on 1 April this year. "I was crying, I couldn't breathe, when I heard," Bennett said. But when Karim went to pick it up at the US embassy in Kabul, he was told there had been a mistake with the online status for a batch of visas, and that his was still being processed.

Karin and Bennett both admit to feeling nervous about meeting again after so long, but both are convinced that a relationship kept alive by phones and internet can last in real life too.

"Everything changes in three years, but when you come to love, it doesn't change," Karim said. "I knew the visa would take a long time and tried to tell her, but because it was her first experience of this she thought it wouldn't be more than six months."

Bennett and Rollins share the stress of waiting for any updates on the immigration process on Facebook pages dotted with photographs and links to news stories about other interpreters hoping for a visa, a forum for applicants in limbo, and articles about the perilous situation of some who have been refused.

The US has promised a special visa programme for Afghan interpreters who took on jobs for its military that exposed them to bombings and battles at work and retaliation at home if what they did for a living was revealed.

But hundreds of applicants have been waiting for years, and a growing number say they have been turned down because the US state department believes there is no serious threat against their lives.

One picture from this autumn shows a young Afghan, smiling with other interpreters in US military uniform. News had just filtered through that he had been killed while off-duty.

Karim and Zia's cases are unusual because they are applying for fiance or spouse visas. But both have the same years of service and testimonials to their bravery and loyalty as the other applicants – and the same agonising wait.

"There must be some reason why we have to be apart for so long," Rollins said. "Everything else has been so perfect, and then the visa is just not happening. I just have to remember that it is going to work out in the end."

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