The man at the center of a case that could legalize gay marriage across the country shared the heartbreaking details of his fight for equality, his partner's terminal illness and their marriage on an airport tarmac on Saturday.

Jim Obergefell recounted the touching story to a crowd of nearly 1,000 people on Saturday at HRC Houston's 18th Annual Gala. Obergefell is the lead plaintiff in the Ohio marriage case pending before the Supreme Court. He told the crowd on Saturday that he's looking forward to walking up the courthouse steps on April 28 when oral arguments are heard in his case and others from Michigan, Kentucky and Tennessee. The cases could prompt the court to legalize same-sex marriage across the county as soon as June. 

But for Obergefell, the journey to the Supreme Court is personal. His partner, John Arthur, was diagnosed with Lou Gehrig's disease in 2011. In 2013, the couple of more than 20 years flew from Ohio in a plane designed to address Arthur's medical needs so they could be married on the tarmac at Baltimore-Washington International Airport. When they returned to Ohio, the couple sued for recognition of their marriage so that Obergefell's name would appear on Arthur's death certificate. Arthur died shortly after their return.

"It wasn't love at first sight for me and John, but it was pretty darn close. We fell in love the third time we met and so we always like to say it was love at third sight," Obergefell said on Saturday (watch video below).

"I never expected to be a caregiver before the age of 50, especially not for the love of my life. But I can think of no better way to keep my promise to protect my life than to care for him 24 hours a day, 7 days a week when he could no longer do that for himself," he added.

The case made its way to the Supreme Court, where Obergefell said he's ready to take the fight for LGBT equality – even if he's an unlikely soldier in the fight.

"I'm humbled to be able to play a small part in moving that fight forward," Obergefell said. 

"We have to stand up not just for ourselves but for every LGBT person who has lived a life of fear not knowing the joy of living the true life they wanted or deserved," he added.

On Monday, Obergefell told his story to U.S. senators.