AceShowbiz -

Casper Smart's infidelity is reportedly the real reason behind his breakup with Jennifer Lopez. Months after they called it quits, reportedly because he chose not to attend a party with her, a source told PEOPLE that the singer actually dumped her longtime boyfriend after he cheated on her again.

Smart was allegedly caught cheating for the first time two years ago. "She kicked him out because he cheated on her and he got caught," the source explained. "It happened two years ago, and he promised he would never do it again and once he did, she was done."

According to the source, Smart has been "begging" Lopez to take him back, but she has been keeping their relationship completely professional. "He's been doing everything he can to get back together," the source claimed. "[He's] working on himself and posting on his Instagram saying that 'Life is Good' and showing off his new leg tattoo that says 'You must embrace the darkness to see the light.' "

The source additionally denied reports claiming that J.Lo decided to end her relationship with Smart after he skipped the party in Hampton to have fun with his friends in Las Vegas. "The truth is, he was cheating and now that it's over he's been begging to come back," the source shared.

"He says he's changed and that he is a new man but recently, on a video shoot for Wisin in Mexico, he was posting videos with bikini-clad dancers and not acting like a guy trying to remedy old habits," the source continued. "He was kicked to the curb not because he did not attend a party with J.Lo but because he was caught having parties of his own. No one has time for that, especially J.Lo."

Smart and Lopez began dating in 2011 following her split from Marc Anthony, with whom she shares two children. The couple briefly broke up in 2014 and split for good back in August. "It wasn't anything dramatic and they were on good terms - it just came to a natural end," a source said of their latest split. "They will remain friends and they see each other."