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Jennifer Lopez is ready to let go -- but Marc Anthony isn't.

Although Lopez has joyously embraced life as a single working mom since the couple announced the end of their seven-year marriage nearly three weeks ago, Anthony is struggling and scrambling big-time, an insider tells the new Us Weekly, out now.

And the Latin crooner sometimes takes it out on his future ex-wife. "His mood shifts from blaming her to begging her to take him back to telling her she is destroying his life," the Lopez source says.

And as the couple hash out the details of an impending divorce, "he's being difficult on every little point...He wants to prolong things so she reconsiders," the insider says.

And while volatile Anthony has been "hard for Jennifer to take," the singer, actress , designer and American Idol judge has stuck to her resolve to break free -- and she's loving every minute.

"She is very happy," another pal tells Us. "She is surrounded by love."

For more on the split -- how Lopez's happy demeanor and time with a sexy male costar "drives him crazy," plus how their twins are doing -- pick up the new Us Weekly, on stands now!