Gay marriage: Why law keeps British and US couple apart
21 June 2013 Last updated at 01:17 BST
The US Supreme Court is due to rule by the end of June on the constitutionality of the Defense of Marriage Act, a federal law which defines marriage as strictly between a man and a woman.
If the high court strikes down the law, known as Doma and signed into law by President Bill Clinton in 1996, it could give same-sex couples the same immigration rights as heterosexual couples.
American David Castro, 34, and Briton Jason Little, 26, got married in New York last year. But they live in separate countries because the US federal government - and thus the country's immigration law - does not recognise New York same-sex marriages or those ratified in any other state.
The couple, who have been together six years, have gained some fame in the gay community for creating Missing Husband - a street art project and a video of the two of them tearfully saying goodbye at Los Angeles International Airport.
The BBC's Regan Morris met David Castro in Los Angeles - and spoke with Jason Little over the internet - to discuss what the Supreme Court case meant to them.
Filmed by the BBC's Maxine Collins