Jennifer Lopez ended the engagement, one of her publicists told The Associated Press on Thursday.
A spokesman for Lopez at Dan Klores Communications said in a statement: "I am confirming the reports that Jennifer Lopez has ended her engagement to Ben Affleck. At this difficult time, we ask that you respect her privacy."
People and Us Weekly magazines first reported the breakup on their Web sites Thursday afternoon.
"It's really not a surprise," says People magazine senior editor and The Early Show contributor Jess Cagle. "We had seen signs maybe they were going to break up. They had not been spending a lot of time together. Last year, for example, they were at the Sundance film together. They were joined at the hip, caused a media frenzy. This year, he was there alone."
Affleck's publicist, Ken Sunshine, would only say: "As usual, we never comment on the private lives of our clients."
Cagle notes, "Either he is being a gentleman and letting her do that or she did not want a third divorce under her belt and realized that they were very, very different people. He's a blue collar guy from Boston and she is a woman who loves clothes and fashion and would much rather be at her mansion in Miami and dancing all night rather than going to a Red Sox game."
Lopez, 34, and Affleck, 31, have been the subject of near-constant media scrutiny for the past year and a half.
In the video for Lopez's 2002 hit "Jenny From the Block," in which she makes fun of the paparazzi, Affleck rubs her legendary posterior while basking in the sunshine on a boat. In another song from her album "This Is Me ... Then," titled "Dear Ben," she professes her affection for Affleck.
But then their romantic comedy, "Gigli," was considered the cinematic disaster of the year before it even debuted in August.
Cagle says, "I believe if people had loved that movie and said, 'This is the next Hepburn and Tracy,' they would still be together."
They were supposed to have married a month later, but abruptly postponed their lavish plans "due to the excessive media attention surrounding our wedding."
Since then, the media has followed their every move, keeping track of who Lopez was with and whether she wore her 6.1-carat pink diamond Harry Winston engagement ring. Even a routine trip to a Georgia courthouse to get a gun license for Affleck drew a horde of photographers and celebrity reporters.
The protocol is that Lopez will give the ring back.
This would have been the first wedding for Affleck. Lopez has been married twice before — to waiter Ojani Noa in 1997 and to dancer Cris Judd in 2001. Noa lasted a little more than a year; Judd for nine months.
She also famously dated Sean "P. Diddy" Combs — back when he was still "Puffy" — for two years before the couple broke up in February 2001.
Now the former couple will appear on screen together again in "Jersey Girl," due out March 19.
Lopez plays Affleck's wife, but she dies 12 minutes into the movie.
Lopez is supposed to be a presenter at the Golden Globes. Cagle says, "She'll show up but may not do the red carpet because you can imagine what a feeding frenzy that will be. I expect both will put their best face forward and not go into hiding."