'The Kids Were Crying For Him' -- Source Reveals Casper Smart's Bond With JLo's Children & Why He'll Always Be In Their Life

Jennifer Lopez and ex-boyfriend Casper Smart made a surprising appearance when they were photographed together on Monday, but RadarOnline.com has exclusively learned it has nothing to do with the two of them  — it's for the kids.

In fact, a source tells RadarOnline.com the only reason the couple stayed in a relationship as long as they did in the first place was for the sake of her children.

"They wanted it to end for quite a while, but the only reason Casper stayed was for those kids because he loves them so much," an insider told RadarOnline.com.

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And it seems the feeling was mutual, because the source reveals that Smart and Lopez's recent rendezvous was because the kids were begging to see her ex.

"Casper will always be part of their lives," the source said.

"The kids were crying for him. With their parents divorced and both so busy, Casper was really the most stable parental figure in their life!"

The kids are twins Max and Emme, 6, from Lopez's marriage with Marc Anthony.

Since the breakup, it's been rumored that Lopez is dating Dancing With The Stars hunk Maksim Chmerkovskiy — but both deny any romance.

Meanwhile, Smart was plagued by reports of online sexting and sex romps with numerous transgender  models — adamantly denying the claims.

"The kids will always come first for Casper," the source added.