Jennifer Lopez has become a “fitness robot” who is obsessed with her body, and it caused problems in her relationship with boyfriend Casper Smart, RadarOnline.com has exclusively learned. 
 
 Lopez, 44, recently broke up with Smart, 26, in the wake of embarrassing allegations that he had “sexted” transgender model Sofie Vissa. 
 
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 But now a source is telling Radar that Lopez’s body issues also played a role in the two drifting apart. 
 
 “Jennifer’s obsession with her own body is out of control,” the source said. “There’s no doubt she’s worked herself into the ground to achieve her killer shape.” 
 
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 Although Lopez is hailed as an incredibly fit forty-something, the source revealed her focus on fitness has affected those around her, especially Smart. 
 
 “In the end, Jen and Casper had nothing else to talk about except diet and exercise stuff, and that was exactly how she wanted it,” the source said. 
 
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 Lopez’s trainer, Tracy Anderson, recently told Allure Magazine that the single mom of twins follows a portion-controlled diet and participates in rigorous 90-minute workouts. 
 
 The singer and American Idol judge told British Glamour Magazine herself earlier this year, “I’ve worked out my whole life and I’ve been incredibly disciplined when I needed to be.” 
 
 Although Lopez said she sometimes wants to relax in a beach chair, she motivates herself to do otherwise. 
 
 “At the same time that very ambitious, determined girl inside me is like, ‘Come on, let’s be in the best shape ever and really show everybody.’” 
 
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 The source noted, “Jen obviously looks great, but she has become a health and fitness bore and it’s driving those close to her nuts.” 
 
 “It’s no exaggeration to say that Jen is obsessed with her body and, other than her kids, nothing else comes even close to being as important to her as staying in shape. 
 
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 “Jennifer used to love talking about fashion and movies with her girlfriends, but now it’s ‘this cleanse,’ ‘that workout routine.’ She’s like a fitness robot who has nothing else in her life!” ||||| Jennifer Lopez is ready to dump her boy-toy Casper Smart following further lurid claims that he’s been sexting transsexual models behind her back. 
 
 Sources said Lopez, who is preparing for Wednesday’s free concert in front of thousands at Pelham Bay Park and also appeared in The Bronx to promote a healthy eating initiative, is furious that Smart’s alleged extra-curricular activities could overshadow her work. 
 
 On Sunday, “Jenny From the Block” appeared at the Bronx event to promote the Center for Healthy Childhood at the Montefiore Medical Center, which received $250,000 from her Lopez Family Foundation. 
 
 But on Monday, thedirty.com hit Lopez, 44, with details of 27-year-old Smart’s second alleged sexting transgression, this time with a transgendered female model named Xristina Marie. 
 
 A source told us of the growing frustration in the Lopez camp over Smart’s antics: “She’s coming back to The Bronx and the only thing anyone can talk about is her toyboy and the transsexuals.” 
 
 Another source tells us, “Jennifer is getting tired of all these allegations. She doesn’t need this drama and is ready to move on.” 
 
 While reps for Lopez declined to comment last night, the second source sniffed, “The focus should be on her work for the foundation and the concert, not Casper Smart.” 
 
 The latest Smart uproar comes after transgender bikini model Sofie Vissa tried to shop a story claiming that she shared intimate Instagram messages with Lopez’s boyfriend, claiming to have screenshots of their alleged chats as well as “naked images of Casper Smart,” according to thedirty.com editor Nik Richie, who first exposed the Anthony Weiner sexting scandal. 
 
 Smart, who has since become a choreographer and creative director, first met Lopez when he was a backup dancer. His representatives did not respond to our e-mails for comment Monday night.
– We knew things were not looking good between Jennifer Lopez and Casper Smart, and last week the world discovered they are, in fact, over. But, though rumors have flown that the breakup had something to do with Smart's interest in transsexual models, sources tell Radar the truth is a little more mundane. J.Lo is simply "obsessed with her body," a source explains, and has become a "fitness robot" who reportedly sticks to a regimen of 90-minute workouts. She and Smart "had nothing else to talk about except diet and exercise stuff," the source says. "She has become a health and fitness bore. ... It's 'this cleanse,' 'that workout routine,'" all the time. (Click to read about 7 unusual celebrity workouts.)