Alaska Airlines has apologized after a gay couple said they were separated on a flight so a straight couple could sit together instead.

Earlier this week, David Cooley said he and his partner had boarded a flight with the airline from New York City to Los Angeles when a flight attendant approached the pair and asked if one of them was willing to give up their seat so a couple could sit together. Cooley said he informed the cabin crew member that he and his partner were also a couple, but he was still told that he and his partner could either sit in different seats or deplane.

“I have never been so discriminated against while traveling before,” Cooley wrote on Facebook. “After my traveling companion and I had been seated in our assigned seats for a while, we were approached by the flight attendant and my companion was asked to move from his premium seat to coach, so a couple could sit together. I explained that we were a couple and wanted to sit together. He was given a choice to either give up the premium seat and move to coach or get off the plane. We could not bear the feeling of humiliation for an entire cross-country flight and left the plane.”

Cooley added he was in disbelief that in 2018 an airline could make such a discriminatory mistake.

“We will never be flying Alaska Airlines or their recently purchased Virgin Airlines Group ever again. Thank you to Delta Air Lines for getting us home safe.”

Though this may seem like a one-off mistake, Naomi Goldberg, policy and research director at the Movement Advancement Project, told The New York Times that actions like this are more pervasive than you probably think. She pointed to a 2017 survey from the Center for American Progress, which shows 36 percent of L.G.B.T. people attempt to hide personal relationships for fear of discrimination.

“Obviously, this couple’s experience should not have happened,” Goldberg told The New York Times. “Whether or not it’s in line with Alaska Airlines' values, or even policies, it did happen. My hope would be the company would obviously do some internal work or have conversations about what it means to serve the public and be open to all.”

For its part, Alaska Airlines shared its apology to Cooley on Twitter. It read in part, “This unfortunate incident was caused by a seating mix-up on a full flight. It’s our policy to keep all families seated together whenever possible. That didn’t happen here. We are sorry for the situation and did not intend to make Mr. Cooley and his partner feel uncomfortable in any way.”

Cooley has accepted the airline’s apology and noted in a tweet that they are "discussing making things right."