Relationships Galore...

ON:

RIHANNA AND CHRIS BROWN
BRITNEY SPEARS AND MEL GIBSON?!?!

OFF:

KATE HUDSON AND OWEN WILSON
SHANIA TWAIN AND MUTT LANGE


- Rihanna and Chris celebrated his 19th birthday this week (can you believe he's only 19?!?) and attended the Kanye West concert the next night. And both times, were showing some serious PDA!!!


- Britney Spears and Mel Gibson are headed to Costa Rica where they will vacation with the singer's father and Gibson's wife, a source tells PEOPLE. "They're just going away for a few days to relax," says a source. The group plan to stay at Gibson's Costa Rican home. They will be back early next week. The unlikely pair were first spotted together back in mid-March when they dined at Russian restaurant Romanov in Studio City. However, it wasn't their first meeting. Gibson and Spears and their families met a number of times after the pop star was hospitalized in February, a different source told PEOPLE at the time. "Mel and his wife Robin clearly saw a woman in crisis and wanted to extend themselves in any way possible," the source said.

- Kate and Owen have called it quits, less than two months after rekindling their romance in Miami. "It was a pretty bad breakup," says a Wilson pal. "Owen said it was a tough one. He definitely doesn't want to dwell on it. He wants to put it behind him."

- "Shania Twain and her husband, music producer Robert 'Mutt' Lange, are separating after 14 years of marriage," spokesman Jason Owen says in a statement. "This is a private matter and there will be no further comment at this time."


Sigh, the ups and downs of love...