Here’s an idea that would have been good business: The Patriot Center could have sold twice as many tickets to Lionel Richie’s concert in Fairfax County on Wednesday, given that many couples shared a single seat, snuggling on each other’s laps during a love-fest of a concert.

Richie, 64, didn’t even pretend he was going to play anything new on the fifth stop of his month-long “All The Hits All Night Long” tour. “I am prepared to sing every song I can remember,” he announced smoothly. “The good news is, we’re going to sing all the songs. The bad news is, I hope I can remember them.”

Richie’s been crooning the same songs for so long — “Penny Lover,” “Truly,” “Ballerina Girl,” “Lady” — that he could probably sing them in his sleep. The same could be said of the members of the predominantly middle-aged crowd.

“We have known each other a long time,” he cooed onstage, flashing a big smile at the ladies in the front row who weren’t seat-sharing but instead jumping up and down and shrieking.

Richie instructed people in the arena to go back in time and reminisce about when they first heard his songs, and “where you were, what you were doing and who you were doing it with.” From the dreamy looks on many people’s faces, those were some happy memories.

What could have been an in­cred­ibly sleepy affair with so many slow love songs actually zoomed by, as Richie basked in his former glory, strolling back and forth across the stage, pausing to tell the history of some of his (and the Commodores’) most well-known hits, including “Still,” “Stuck On You” and “Three Times a Lady.”

Richie’s voice, strained at some points, still provided enough power for bursts of energy for “Dancing on the Ceiling” and the island-themed smash “All Night Long.” Although it was a little unsettling to see Richie (who’s Grandpa Lionel now, he reminded everyone, although his grandkids call him Pop Pop) make the hourglass-figure hand motions with “Brick House.”

But Richie embraced the cheesiness, with some especially awkward dancing: lots of hip swivels and pointing of index fingers in the air. Easily winded, he caught his breath a couple times as he soaked in the screams from the audience and wiped the sweat from his forehead with a small towel.

No mention was made of his recent return to pop-culture relevance with last year’s “Tuskegee,” a compilation of countrified versions of his songs featuring guest stars that include Kenny Chesney and Jason Aldean. It was his first No. 1 album in 25 years.

Instead, the concert remained all about the past, culminating in a long shout-out to Michael Jackson when Richie closed with “We Are the World.”

Curiously, the feel-good group hug of an evening ended on a somber note. What really disturbed Jackson, Richie recalled, was that after they wrote the song, it didn’t seem to change anything.

“He couldn’t figure out why we didn’t save the world,” Richie said, before breaking into the ballad. “And why we couldn’t make a difference.”