It all started in the summer of 1984. Terri Seymour was only 19 when she locked eyes with the handsome Marine across the dance floor of the Virginia Beach campgrounds pavilion.

Robert Clark Thomas, then 26 and visiting for the weekend with a couple of military buddies, finally worked up the nerve up to approach her and ask her to dance. Terri excitedly agreed.

The two clogged in perfect harmony to the bluegrass band and chatted afterward for hours. They discovered their hometowns were only 20 minutes apart; although Clark was stationed at Camp Geiger in North Carolina, his family home was in Stafford County and Terri lived in Arlington County.

At the end of the night, he walked her back to her campsite and kissed her goodnight. “Immediately, it was just sparks,” Clark says. They made plans to see each other as soon as possible.

The two were inseparable for about a year, traveling back and forth on weekends for visits and starting their long-distance romance. “Every time I took him back to Camp [Geiger], he had to peel me off of him,” Terri recalls. “Literally, I mean I would just wrap my fingers around him and tell him, ‘I’m not going anywhere.’ ”

Then came the news that Clark would be deployed overseas in the Mediterranean. Terri, nervous about the distance, preemptively broke things off. “I was 19. I was stupid, young and had no frame of reference,” she remembers. “I knew I loved him, but I didn’t realize what I had yet.”

After their painful parting in 1985, Clark served his time in the Marines, moved back to Massachusetts and got married. Terri went to college, married and divorced twice, and had two kids (Brenda, now 11, and Eli, now 9).

For Terri, a senior manager at General Dynamics Advanced Information Systems of Fairfax and lead singer of the local rock band Cry Ice, Clark was always “the one that got away.”

“I never really wanted to admit it, but I was constantly thinking of him. [For example,] the man I married was his body size, and I dated other Marines,” Terri said. “All my life, I kept trying to refill his shoes.”

Clark, a railroad electrical technician, felt the same way. He missed her terribly and had always regretted how the pair had left things.

He decided to search the Internet to find Terri’s e-mail address to send her a Christmas card in 2011. A small but significant gesture, he hoped it might reconnect them.

That winter was tough for Terri. She was still dealing with the aftermath of a messy divorce and had been hospitalized with Bell’s palsy and a nasty case of shingles. When she received Clark’s note, she was happy but skeptical. Clark was, at the time, married.

He had an unexplainable feeling that something was wrong with Terri, he says, which pushed him to try contacting her again, one last time. “I had a . . . gut feeling that something was just not right,” he recalls. “I had to check in on her.”

This time, Terri responded. She e-mailed him right back and tentatively asked — is it really you? Clark quickly called her to prove his identity. A day later, the pair, who hadn’t talked for 26 years, ended up chatting on the phone for four hours. Both exchanged “I love yous” at the end of the conversation.

“It just came out. It seemed so natural,” Clark says. Before they knew it, they were texting and chatting over the phone and Skype frequently.

A close relationship quickly developed. Three months later, Clark, now 56, and Terri, now 49, met up in person and returned to the place where sparks first flew — the Virginia Beach campgrounds.

“We didn’t miss a beat,” Terri remembers. “It was like no time had passed.” The pair listened to their songs, including “Panama” by Van Halen and “Rock You Like a Hurricane” by Scorpions, the whole way down.

Clark was in the process of moving to Arlington when his late father, who had received an Alzheimer’s diagnosis, took a turn for the worse. Instead, Clark moved to Florida to take care of him.

“If you look in the dictionary under the term good boy, Clark is there,” Terri says. “He kept his entire family together. His nickname is Superman for a reason.”

Frustrated with the distance, Terri broke off communication. “We did the math, and it was three weeks and three days total in three years we saw each other,” Clark said.

But months later, the pair patched things up. “Both of us would come back going, ‘I cannot do this. I cannot live without you,’ ” Terri says. “I don’t know why we kept thinking we could.” Clark’s divorce was finalized in July 2013.

On Dec. 4, he drove up from Florida to celebrate Terri’s daughter’s birthday and help pick out the family Christmas tree. That night, after privately asking both of her children for their permission, he got down on one knee and proposed. He moved into Terri’s Arlington home in late December.

The pair organized the wedding festivities in just 20 days. “We decided we were sick of playing games,” he says. Between the proposal and the wedding, they got matching tattoos of an interlocked Superman and Wonder Woman logo.

On Christmas Eve, they exchanged vows at Walker Chapel United Methodist Church in Arlington in front of 15 close friends and family members. Both of her children were in the wedding party, and her son escorted her down the aisle.

The next afternoon, on Christmas, the pair headed to Las Vegas, where they renewed their vows at the Graceland Wedding Chapel in a ceremony officiated by an Elvis Presley impersonator.

“We were able to have the nice heaven version and the fun, Sin City version,” Terri joked.

Terri and Clark are grateful for their wedding journey. “Our devotion, dedication and the deep love we have for one another . . . you don’t see it very often,” Clark said after the wedding. “It’s a true love that has never been lost.”