(CNN) -

Anthony Sullivan was a young Australian with Robert Redford looks. Richard Adams emigrated from the Philippines as a child and became an American citizen. The two met in Los Angeles, fell in love and got married in Boulder, Colorado -- long before any state legalized same-sex marriage.

County Clerk Clela Rorex issued the gay couple a marriage license at 11 a.m., April 21, 1975.

Nothing in the Colorado marriage code mentioned same-sex marriage, and Rorex signed licenses for six couples before the district attorney intervened and put an end to them. But the licenses were never rescinded.

Sullivan and Adams believed their marriage was legal and embarked on a decades-long struggle to attain permanent resident status for Sullivan.

They became the first gay couple to sue the federal government for recognition of their marriage, effectively launching a movement that helped lead to the Supreme Court's ruling a year ago that struck down the Defense of Marriage Act, which defined marriage as between a man and a woman.

But even now, a year after that historic ruling, Sullivan, 72, remains in America, undocumented.

In April, he filed a motion for the government to reopen his case and grant him a green card.

Federal immigration law says a U.S. citizen or green card holder can sponsor a spouse so that they can remain together in America. But because of DOMA, the law did not afford that right to binational gay couples.

After DOMA's demise, about 40,000 such couples became eligible for immigration rights. Previously, they were forced to choose between love and country -- and many of them lived in exile to be together.

"The DOMA ruling completely changed the landscape," said Michael Sisitzky, an attorney with Immigration Equality, an organization that has been working with same-sex binational couples for two decades.

It was a watershed moment, and within one week of the ruling, Immigration Equality heard from 1,500 couples seeking help. That's more than the total number of inquiries the group got the year before, Sisitzky said.

"It was as if a light switch had gone off," he said. "LGBT couples go through the same process now as straight couples."

However, some people, like Sullivan, have been left behind, said his attorney, Lavi Soloway.

Six months before the DOMA ruling, Sullivan's spouse died. Soloway said gay and lesbian widows and widowers are fighting to get their marriages recognized even though they no longer have a spouse who can sponsor them for a visa.

Sullivan hopes that the U.S. Citizenship and Immigration Service will allow him to live in the United States, as he has done for the past 40 years, legally.

"Common sense says that my petition should be accepted. Decency also says it should be accepted," Sullivan said. "At the moment, I am just living my life day to day. "

A license and a letter

At 29, Sullivan left home in Sydney, Australia, and was in the middle of an around-the-world trip when he stumbled upon Adams at a gay bar called The Closet in Los Angeles. It was Cinco de Mayo, 1971.

The two agreed to meet for a date the next day at Greta Garbo's star on Hollywood Boulevard. Soon after, they knew they wanted to spend the rest of their lives together.

But Sullivan was on a tourist visa in the United States. He was not permitted to work. He would have to leave the country when his visa expired. They began to think about ways they could stay together.

There was no country in the world then that allowed immigration rights for same-sex partners, nowhere they could go. Sullivan remained in the country -- illegally.

Then, on television one day, they heard the most incredible news: a Colorado clerk had issued a marriage license to two men. Sullivan and Adams immediately made plans to fly to Boulder.

Rorex, the Boulder County clerk, was 31, wore her skirts short and her hair long. She'd joined the National Organization for Women and was swept up in the movement for equal rights. She surprised even herself by winning the clerk's race.

She'd been on the job only three months when a couple from Colorado Springs -- David McCord and David Zamora -- showed up wanting to get married. After she learned from the district attorney that nothing in the marriage code referred to gay marriages as illegal, Rorex granted the two men their wish.

She did not know any gay people; she'd grown up in the small town of Steamboat Springs, Colorado, before it became a skiing haven. Her world was pretty insular.