The pop star, actress and American Idol judge, 44, has split from her boyfriend of 2½ years, choreographer and dancer Casper Smart, a source confirms to PEOPLE.
"They initially split about six weeks ago, but that can take a little time to extricate. But they've definitely broken up," says the source, adding, "The relationship had just run its course."
The source also says, "Jennifer is actually doing really well and working hard."
There had been hints in recent weeks that the relationship was on the rocks, with a source telling PEOPLE that the couple had "hit a rough patch" a couple of months ago.
More recently there had been reports claiming that Smart, 27, a former backup dancer for Lopez, had sent Instagram photos and steamy messages to somebody else.
Lopez and Smart first got together in late 2011. At the time, a source told PEOPLE it was "a fun fling" and "not meant to turn into anything more," but the couple stayed together.
Lopez was always noncommittal, however, when asked if she would get married for a fourth time.
"I don't know. We'll see. I don't know," she said in January. "You know, I've always believed in that institution. I believe in it, but it is difficult. I've had my challenges, but at the same time I believe in love, and I think that is the main thing."
With reporting by ELIZABETH LEONARD