Marc Anthony Throwing "Tantrums" Over Casper Smart and J. Lo, Source Claims

With the relationship between Casper Smart and Jennifer Lopez heating up, source say the latter's ex-husband is boiling over.

Us Weekly reports that Anthony is "going nuts" over J. Lo moving on so quickly with her 24-year old backup dancer, "throwing fits and tantrums" and losing "a lot of weight" over the last few weeks.

But apparently Anthony isn't the only one taking issue with Smart.

The tabloid has also talked to friends of  Lopez who aren't sure if Casper is the right man for her, either. Says one insider of these pals, and of the star with three marriages on her record:

"They don't feel Casper is good enough for her. They are worried because she really puts her heart out there for love."

[Photos: WENN.com]