Meg Ryan, John Mellencamp Call It Quits

Is there something in the water? Hollywood has been hit with a rash of break-ups:

• After more than three years together, Meg Ryan and John Mellencamp are over, People reports. "It was the long distance that ultimately was the cause," says one source; Ryan, 52, lives in New York while Mellencamp, 62, lives in Indiana.
• Michelle Rodriguez and Zac Efron weren't together nearly so long, but they, too, are finished after almost two months of dating, Us reports. "Michelle is going to do her own thing. Zac knew this about her when he got with her," one source says. "He's very into her though, and perhaps more than she's into him." Rodriguez, 36, and Efron, 26, reportedly had a big fight in Ibiza that prompted the split.

• In slightly more D-list news, Jersey Shore couple Ronnie Magro and Sammi "Sweetheart" Giancola are done for good after an on-again, off-again five-year relationship, Magro tells People. "We were drifting apart and not really spending any time together," he says. "She's a great girl, but we were growing distant."
• And, though there's no official word on this yet, multiple outlets are reporting that Mariah Carey and Nick Cannon are all but divorced. Lawyers have been negotiating property and custody agreements for months, according to TMZ, and the couple has been living separately since May. According to Page Six's sources, Carey, 45, thinks Cannon, 33, might have cheated.