Eduardo Yanga is challenging an order for him to vacate the property in Larne, following the independent cleric’s death.
Mr Yanga and Bishop Buckley lived together in the Catholic Church-owned house at Princes Garden after they were married in a civil ceremony back in 2010.
Two years later the outspoken clergyman settled a legal battle over seeking “squatters rights” to stay in the property where members of his Oratory congregation gathered to worship.
Bishop Buckey, who was subsequently convicted of conducting sham marriages, died in May 2024 at the age of 72.
In December last year the Trustees of the Catholic Parish of Larne and the Diocese of Down and Connor obtained a High Court order for possession of the premises.
Ruling that any tenancy agreement with the late clergyman did not transfer to his partner, a judge gave Mr Yanga one month to quit the property.
He has now lodged an appeal in a bid to have the order overturned.
Representing himself at a preliminary hearing, Mr Yanga argued that his civil partnership with Bishop Buckley predated the settlement which allowed them to continue living together in the house.
"My life was an open book, (the Diocese) should have given me a tenancy agreement,” he told the Court of Appeal.
"I’m not just a visitor, but a legal partner. I treated the place as my family home and wanted to live in it as happily as I could, work and pay my taxes.”
Counsel for the Diocese insisted there had only been a “caretaker agreement” with Bishop Buckley as previous tenant.
"Mr Yanga was there at the invitation of the licensee in the premises,” the barrister said. “When the licensee passed away last year then the plaintiff sought possession of the premises.”
He claimed Mr Yanga has little chance of establishing that the order should be reversed.
"Our position is quite simply that it doesn’t raise any point of law which has a reasonable prospect of success, or is coherent in making a legal argument,” the barrister added.
Following submissions Lady Chief Justice Dame Siobhan Keegan listed the appeal for a full hearing in May.