As if her Fiat fallout and lawsuit weren't enough of a headache, here comes more drama for Jennifer Lopez. Us Weekly reports that estranged, soon-to-be-ex husband Marc Anthony is throwing "fits and tantrums" over her new relationship with backup dancer Casper Smart.

A source told Us that Anthony, 43, is "going nuts" about Lopez's new love -- and that it may even be affecting his health. "He has fits and tantrums and is very stressed," the source said, adding that Anthony "lost a lot of weight." To be fair, Anthony's rep told the mag that he's "been the same weight most of his life" -- and he's always been thin -- so we're taking this part with a grain of salt.

Lopez, 42, has been hot and heavy with Smart, 24 for about a month now. She even spent Thanksgiving with Smart and her three-year-old twins (fathered by Anthony), Max and Emme, and introduced him to some of her family members and friends. How did they like him? It depends on what gossip you believe.  Sources told Us Weekly that J. Lo's pals aren't fans. "They don't feel Casper is good enough for her," a source said.  "They are worried because she really puts her heart out there for love."

However, last month sources told Us Weekly that Smart was pretty well-liked by the 'Papi' singer's posse, especially her tykes. "Casper was great with the kids," a source told the mag. "He was twirling them around and doing flips with Emme and she seemed very comfortable with him."

Perhaps Anthony has not so much a problem with who the 'American Idol' judge is dating so much as how fast she's moving. In October, Lopez was linked to actor Bradley Cooper shortly before she started jet setting with Smart. While we can understand Anthony's concern -- she is the mother of his kids, after all, and anyone in her life will affect them -- perhaps instead of throwing temper tantrums, he should trust that Jenny from the Block is smart enough to take care of herself and learn to move on.