David Ford, the leader of the Alliance Party, left his position as an elder at Second Donegore Presbyterian Church in Ballyclare, County Antrim, amid criticism from members about his views.
He, and his party, have come out in support of same sex weddings in Northern Ireland, which is the only part of the UK yet to legalise gay marriage.
Speaking to the BBC's Nolan Show he said he was still "choked" by the event.
He said: "It saddened me that there was, if I may put it, a lack of understanding from some people about the role I had as a legislator, compared to the role I have within the church."
The Alliance Party, he said, respected churches being able to "practise and define their own beliefs".
Legalising gay marriage was about "providing equality in the way that the public receives services from the state", he said.
He stressed civil marriage was not an issue for the church and he had his own beliefs.
He added: "But in terms of civil society, the services which are provided, I don't believe that it is for those of us who are in the heterosexual majority to tell people who are in the homosexual minority that they're not being discriminated against, when they feel that they are being discriminated against."
Mr Ford told the BBC he still attends the same church but it "hurts" not being in a leadership role anymore.
"There aren't tears but there's a slight choke in my voice," he said.