After changes to the law allowing same-sex marriage in England, Scotland and Wales, Northern Ireland is now the only place in the UK where gay couples are barred by law from getting wed.
Indeed, gay couples from Northern Ireland who get married in another part of the UK cannot currently even have their marriage recognised when they return home across the Irish Sea. Instead, the Northern Ireland authorities deem such marriages to be civil partnerships, which are available to gay couples in the region.
The couple, who married in England last year, have launched a legal challenge in Belfast's High Court to have their marriage recognised as lawful in Northern Ireland.
The Westminster legislation, which brought same-sex marriage to England and Wales in March 2014, contains a provision which forbids the recognition of such marriages in Northern Ireland.
Amnesty International thinks that the law is in conflict with international human rights standards, which say that states may not discriminate with regards to the right to marry and found a family on the basis of sexual orientation or gender identity.
The case, announced today, is being supported by local LGBTI group, The Rainbow Project. It has been welcomed by Amnesty, which previously predicted a legal challenge if Northern Ireland's politicians failed to legislate for equal marriage rights.
Three times in 18 months the issue of same-sex marriage has come before the Northern Ireland Assembly. Three times Stormont's political representatives have rejected it, with the hard-line DUP even threatening to use the 'petition of concern' mechanism (originally designed to protect minorities) to veto the equality proposals.
As on so many issues, the politicians lag behind the people. The 2012 NI Life and Times survey showed a clear majority (almost two to one) of people in Northern Ireland back the legalisation of same-sex marriage. Popular support has likely grown further in the last two years, just as it has in the Republic, which looks set to back the measure in a May referendum.
With Northern Ireland's politicians making the region a discriminatory backwater for the gay and lesbian community, the region's same-sex couples have been left with no choice but to pursue equality through the courts.
And not for the first time.
Homosexuality was only finally decriminalised in Northern Ireland in 1982 as a result of successful case brought to the European Court on Human Rights. Again, in 2013, it was the courts which upheld the right of the Northern Ireland's gay couples to offer adoption. As recently as last week, a judge in Belfast found that a former Health Minister's ban on the donation of blood from gay men in Northern Ireland, was "infected by apparent bias" and influenced by religious beliefs.
The latest court challenge may be the first in a series of cases necessary to ensure that gay people in every part of the UK have an equal right to marry the person they love.