Billy Crystal Shares the Secret to His 54

Billy Crystal has simple advice for more than 50 years of marriage.

The When Harry Met Sally actor, 76, shared with PEOPLE at the premiere of his new AppleTV+ series, Before , the secret behind having such a lengthy marriage with his wife, Janice Crystal .

"Respect, humor, honesty, and respect for our lives as individuals and as a couple," the six-time Emmy winner exclusively tells PEOPLE.

"Just enjoy all the time that you have together," he adds. "Through the thin and the thinner."

The couple first met as teenagers living in Long Beach, N.Y., in the summer of 1966. They tied the knot on June 4, 1970, and welcomed daughters Jennifer Crystal Foley on Jan. 26, 1973, and Lindsay Crystal on Oct. 21, 1977.

At the Before premiere, he also tells PEOPLE about parenting Jennifer and Lindsay with Janice, 75.

"Oh, children change everything," he tells PEOPLE. "When I first became a dad back in [1973], Janice was working, and I was starting my career as a stand-up at night. So, during the day, I was 'Mr. Mom' and that changed my life totally."

"The responsibility as a 25-year-old with an infant that can't get through the day without you," he continues. "When you learn that you can love something much more than yourself, it was the greatest experience in my life as a person."

"That's been my total effort of my life is to leave the world with two amazing daughters — grown women now, mothers of their own," he says, adding, "And that they then teach their children/our four grandchildren what it means the responsibility in our world, which is changing constantly."

In a May 2021 interview on The Kelly Clarkson Show , he said that through their laughter and jokes, they "still learn from each other."

"We still love being together," he told host Kelly Clarkson . "We just have so much fun and keep discovering new things about each other. And I think that's the most important thing is to still always be curious and find out more about each other."

Ahead of their 50 year anniversary in 2020, he also told The Sydney Morning Herald that he's strived to replicate his parents' relationship. "My parents always looked like they loved being together," he told the outlet. "That's what I took from them, and that's how my wife and I are. I still feel like we're dating."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

Before premieres on Apple TV+ on Friday, Oct. 25, with the first two episodes, followed by weekly releases through Nov. 15.