Christian staff at The Venue at Waterstone in Celina, northern Texas insisted they "love all people" after they cancelled an enquiry made by Aaron Lucero and Jeff Cannon.
In a statement seen by NBC 5 Dallas-Fort Worth, they said: "We are a family of believers. We love all people because Christ first loved us; Jeffrey and Aaron included.
"We cannot violate the convictions God has placed within us. In love, we would never affirm anyone in something that was to their detriment."
Publishing a lengthy post on Facebook, Mr Lucero said The Venue at Waterstone had "tried to disguise its discrimination" by not making its stance of same-sex weddings visible on its website.
He claimed the couple were not informed about the unavailability of the venue until the night before they were due to visit on 20th January.
Mr Lucero added: "The reason we are sharing this is not because The Venue at Waterstone refuses to host same-sex weddings; it is because they refuse to publicize their discriminatory policy on their website.
"They want to discriminate against the LGBTQ+ [lesbian, gay, bisexual, transgender, queer, plus] community in private."
It is currently legal to discriminate against people on the basis of sexual orientation and gender identity, according to the American Civil Liberties Union.
Mr Lucero, who became engaged to Mr Cannon last November, said they had got "very excited" at the prospect of tying the knot at The Venue at Waterstone next year.
He added: "This made receiving the news last night all the more heart-breaking."
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