Backstreet Boys’ Brian Littrell and his wife Leighanne share exclusive photos from their intimate 20th wedding anniversary celebration with PEOPLE

Brian and Leighanne Littrell. PHOTO: BOBBY KLEBANOFF

She’s “The One!”

On Sept. 2, Brian Littrell and his wife Leighanne hit a sweet milestone: two decades of marriage. And according to the couple — who met in 1997 on the set of the Backstreet Boys’ “As Long As You Love Me” music video — they’re happier than ever.

“Who would’ve thunk it? We did it!” Brian told PEOPLE exclusively ahead of an intimate dinner party the couple hosted on Saturday to celebrate. Added Leighanne: “Especially in Hollywood and in this industry, 20 years is like 100 years, actually.”

Over the years, the pair have been a united front as they’ve faced ups and downs, and the key to a joyful marriage has been “a lot of communication and a lot of trust,” says Brian, 45. “Nothing is ever peachy keen and perfect all the time, but being able to grow together instead of growing apart is the big thing.”

With a career that’s often taken him around the world for long stretches of time, Brian says his wife, 51, has been an anchor keeping him grounded.

Littrell’s 20th anniversary dinner. Bobby Klebanoff

Bobby Klebanoff

“I knew she was strong, but I just didn’t know she was that strong. She’s really been the rock of our family. She’s an amazing mom. She’s an amazing friend, and she’s an amazing lover. Sorry, did I say that out loud?” says the singer with a laugh.

Adds Leighanne: “One of the things I loved about him when we first met was if we ever had a problem, he had this willingness to do better for the relationship. It’s that much more now, and he’s grasped again what I loved.”

At the center of the Littrells’ world is their son, Baylee, who turns 18 in November and has been carving out his own musical path.

Brian, Baylee and Leighanne Littrell. Bobby Klebanoff

“It’s such a blessing to see him just continuing to grow into the artist that he is,” says Brian. “He’s an amazing songwriter, he’s an amazing performer, and obviously it does run in his blood, but he’s his own man and we’re just blessed to be a part of it.”

While his dad is a member of an iconic boy band, Baylee tells PEOPLE he also wants to pay his dues. “In the country world, it’s really earning your stripes and getting there,” says the young singer. “I think the biggest lesson I learned from Mom and Dad is just being patient and realizing you’re one fish in a gigantic pond just trying to make it.”

Though it’s been 20 years since Brian saw his bride walk down the aisle — “we separated before midnight after the rehearsal dinner,” recalls Leighanne — the pop star still has vivid memories of the emotional moment.

“The church doors in the back are monstrous, and when the doors opened, Leigh was so far away. I was speechless,” says the star. “It was something that we had worked to get there just to that point to start our lives together, and it’s gotten better ever since.”