A source told the outlet that Lopez, 47, and Smart, 29, have not been together for a few weeks, but "it wasn't anything dramatic."
"They were on good terms -- it just came to a natural end," the source added. "They will remain friends and they see each other, but they are not together. It was very amiable."
The choreographer recently hung out with Lopez backstage at her All I Have show at Planet Hollywood Resort & Casino in Las Vegas, where the pop diva's ex-husband, Marc Anthony, and his girlfriend, Shannon de Lima, were also in attendance. Earlier this week, however, Smart announced via Instagram that he was going to be taking a break from social media.
"New experiment," he wrote. "Gonna try to live old school for a little while. Going back to a time before social media. Gonna focus on personal connections over a type and text existence."
Meanwhile, Lopez has returned to New York City to film Shades of Blue. She was photographed back on set on Wednesday, rocking high-waisted pants and a navy blue blazer over a button-down blouse.
The two first sparked romance rumors in late 2011. While they played coy at first, they eventually went public with their relationship nearly a year later. They called it quits in June 2014, but reunited again in January 2015.
During her guest appearance on the Wendy Williams Show in March, Lopez explained that her on-again, off-again relationship with Smart was "not that dramatic."
"We broke up for a little bit," she explained. "We've done that a couple of times. It's like, bye, then we get back together and then, hi."