"We will always love each other and be best friends," the singer and his actress wife said in a statement. "However, we have mutually decided to separate at this time."
Robin, 36, and 37-year-old Paula — who welcomed son Julian in April 2010 — have weathered a lot together recently, including reports of Robin's infidelity and controversy over his raunchy performance of Blurred Lines at the VMAs with Miley Cyrus. Until now though they have remained united.
"I don't know if I would still be alive in some ways if it wasn't for Paula," the singer told Prestige Hong King Magazine last September. "She's been my rock, my muse, my inspiration and I love her. The whole way."
Speaking in the same interview, his wife added, "I've been there for his down moments and he's been there for mine.
"Life is full of peaks and valleys. Robin has always been a great person to remind me to celebrate now… We're best friends. We laugh a lot."
Multiple sources told US Magazine that the split was a long time coming. "It is not a shock to Robin or Paula, and it is something they have discussed for a long time."
"Their marriage was unravelling for a long time," another insider added.