Just as the Latina singer-actress pens her book about her divorce from salsa singer Mark Anthony, she may need to add another chapter -- about the possible fizzling of her current relationship with her lead choreographer, Casper Smart.

According to The New York Daily News, Lopez, who has been on a quest for true love throughout her career, may soon be calling it off with Smart because the "spark" is gone between the two.

Lopez' spokesperson reportedly denies there is trouble between the two, but the once head-over-heels in love couple hasn't been pictured together in over three weeks now.

"Jennifer is pretty private about the relationship, but she's been hinting that the spark is gone," according to a source close to Lopez, RadarOnline reports. "She's having a hard time ignoring the fact that her head has been telling her for a while that this thing with Casper isn't forever. And now her heart's saying the same thing."

The source adds: "They're obviously in very different places in their lives, and Jennifer wants to take responsibility for her life and not repeat the same mistakes she has made in the past. She enjoyed the relationship for what it is, but now that giddiness has turned to sadness."

Another insider reveals to RadarOnline that during a shoot for Viva Movil in NYC on June 14, "Everyone on set was whispering about the news that J.Lo and Casper broke up."

"She seemed down and looked tired, like she hadn't slept well, the source adds. "She holed up in her trailer for hours when she wasn't needed for her scenes, and asked for vanilla Haagen Dazs ice cream and white flowers. It was obvious she was a million miles away."

During this time, Smart was nature-bound and posted pictures from a solo camping trip on his Instagram around the time of the shoot.

"Jennifer's team started scheduling all her major appearances solo," the source says.

The couple had a brief breakup over the summer but soon reconciled in July, RadarOnline reports.

The 44-year-old "American Idol" judge began dating Smart, who is 26, in October 2011, not long after her split with third husband, Marc Anthony. MSN adds that Lopez has referred to Casper as her "best friend" who gives "endless love and support."