Kristin Cavallari and Stephen Colletti Are 'Just Friends' After Meeting Up for Dinner: Source

Despite sending fans into a frenzy with their recent reunion, there isn't anything romantic going on between Kristin Cavallari and Stephen Colletti, a source tells PEOPLE.

The high school sweethearts and former Laguna Beach stars got together for dinner this week, with Cavallari posting a photo of the two cuddled up on Instagram. But according to the source, the exes, who have kept in touch since the MTV show concluded years ago, are "just friends."

Another source tells PEOPLE that Cavallari met up with another Laguna Beach star, Alex Murrel Johnson, during the day, then grabbed dinner with Colletti.

Cavallari and Colletti's romance was documented on Laguna Beach, which aired for three seasons on MTV from 2004 to 2006. Their relationship — which briefly involved a love triangle with Lauren Conrad — began in high school and ended when Colletti went off to study at University of Southern California.

In her 2016 book Balancing in Heels, Cavallari, 33, wrote about her relationship with Colletti, 34, admitting that she "hated" fighting with him on camera.

"Stephen was the most important thing in my life, and there was nothing I cared about more," she said, according to E! News. "I hated fighting with him on camera because it felt like I was airing all our dirty laundry."

Their outing comes over three months after Cavallari and her husband Jay Cutler, 37, announced their divorce in April. In a joint statement, they said it was just a situation "of two people growing apart" and that they had "nothing but love and respect for one another."

The two, who had been together for 10 years, share three children: sons Jaxon, 6, and Camden, 7, and daughter Saylor, 4.

In May, a source confirmed to PEOPLE that the two had reached a custody agreement after filing for divorce. Cavallari and Cutler agreed to be named "joint primary residential parents," each spending 182.5 days with the kids a year and alternating time on a week-on, week-off basis, according to court documents obtained by PEOPLE.

They will alternate Easter and Thanksgiving, as well as fall and spring breaks, and will split the Christmas holiday.

Cavallari has since moved into a new house, a $5 million Nashville-area estate.