Appearing Thursday on CBS' The Late Show with Stephen Colbert, actor Jim Parsons said that marrying his longtime boyfriend was more meaningful than he expected.

The 44-year-old Parsons is best known for playing Sheldon Cooper in the CBS sitcom The Big Bang Theory.

In May, Parsons married Todd Spiewak, a graphic designer, at the Rainbow Room in New York City. The men have been together for 15 years.

“I didn’t really think we cared about the act of it that much, to be honest with you,” Parsons explained. “And that sounds cold in a way, but I finally thought…well, let’s have a party then for the celebration of, and we’ll go ahead and legalize this thing. And I really thought it would kind of end at that, a party feel. But it was so much more meaningful in the moment to me than I predicted. And it’s been resonantly more meaningful to me afterward than I ever saw coming. I’d been an adult gay person for so long at a time when that wasn’t possible that life was ‘fine,’ you know what I mean?”

“There is an underlying thing a little buzz of something,” he said of marriage. “I keep reminding myself of it. I kind of forget, and then I’m like, ‘We’re a legal thing. Just like mom and dad were.'”

(Related: Ellen DeGeneres advises Jim Parsons to get married, play tennis.)