For many supporters of LGBT rights, the marriage equality movement truly began in earnest in 2004, when a landmark court ruling legalized same-sex marriage in Massachusetts. Unbeknownst to many, however, the first victory for gay marriage actually happened nearly three decades before.

In 1975, a rogue clerk in Boulder County, Colo., named Clela Rorex began issuing marriage licenses to same-sex couples. At the time, the country was so homophobic, and idea of same-sex marriage was so foreign a concept, the United States didn’t even have any laws preventing it.

Tony Sullivan and Richard Adams were one of six same-sex couples to be married by Rorex before a national backlash shut her efforts down.

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“Back then it was illegal to perform a homosexual act,” Sullivan said in an interview this week. “Gay bars were still being raided by police. Same sex marriage was unthinkable. So we knew we’d have a fight on our hands.”

Thirty-nine years later, despite their legal Colorado marriage certificate and the tremendous recent strides the marriage equality movement has made, the fight to have Sullivan and Adams’ marriage recognized by the federal government is still going on—and it’s the subject of a new documentary called Limited Partnership.

Though Adams passed away in 2012, the stakes of his and Sullvan’s marriage-recognition battle are still very high. As an Australian national, Sullivan risks deportation if the federal government does not grant him a green card based on the fact of his being the spouse of an American citizen.

In 1975, Sullivan submitted a green card request to the Immigration and Naturalization Service, using his Colorado marriage license as his legal backing. That document should have been all he needed to secure the same legal residence status that all other bi-national married couples enjoyed at the time.

Instead, he received a denial letter from American immigration officials, and the blatant homophobia of their words continues to shock him to this day.

“You have failed to establish that a bona fide marital relationship can exist between two faggots,” the letter read.

“No one would expect that,” said Sullivan. “Regardless of the opposition, you expect the government to have some dignity.”

At the time, no other country in the world offered permanent residency to same-sex couples, so Sullivan and Adams were forced to go underground in America, living with the constant threat that Sullivan could be deported.

Over the years, they watched as the marriage equality movement grew in the U.S. They saw same-sex marriage legalized in Massachusetts, and, for a brief moment in 2008, in their home state of California.

Yet they refused to get remarried—even if it could have potentially helped Sullivan’s tenuous immigration situation.

“We believed our marriage was legal in Boulder,” said Sullivan. “It was never invalidated. It is still on the record books in Colorado. So we always held we shouldn’t get remarried. Doing so would cast doubt on our initial marriage.”

That level of love and integrity intrigued filmmaker Thomas Miller, who spent more than a decade following Adams and Sullivan for Limited Partnership.

“I started making this documentary just before September 11th,” he said. “My hope then was that it could be part of the dialogue to overthrow DOMA, and to secure broader support for same-sex marriage. We’ve had so many victories in recent years that now my goal is help Tony get citizenship and live as a legal resident, and right the injustice done to him and Richard Adams.”

This past April, Sullivan, now 72, submitted a request to U.S. Citizenship and Immigration Services to have the 1975 immigration denial he received overturned, granting him legal resident status as the widower of an American citizen.

Sullivan said he’s hopeful about his legal chances, given the blatant homophobia expressed in his denial letter. “In a strange way, the faggot letter was a gift,” he said.

But regardless of the outcome of the legal battle, Sullivan said he already felt like a winner.

“Richard and I spent four wonderful decades together. They never did get to separate us. We were together until the end.”