Sipping champagne on a yacht along the coast of Italy in August, Christina Aguilera and Jordan Bratman should have been enjoying a romantic getaway. But the singer, 29, and her music-producer husband, 33, were miserable. With good reason: Their marriage was falling apart. "They were having problems before that trip, and she simply wasn't happy," a close friend of the couple's tells PEOPLE. "They were in the most beautiful place in the world and having the worst time. That was a wake-up call." Soon after, Bratman moved out of their Beverly Hills home. Says the friend: "There are no divorce proceedings at this point. Right now they're just trying to figure things out."

Rumblings of trouble first started when Aguilera-who wed Bratman in an estimated $2 million dream ceremony in Napa Valley, Calif., in 2005-was spotted without her ring last March. And a source close to the singer says that during an earlier separation, while filming her upcoming movie Burlesque, she strayed. There was a time when the pair, who met in 2002, were happy to work through those rough patches. "We're each other's best friends in the whole wide world, so we can get through anything and everything together," she told PEOPLE in 2007. "It makes you stronger to get through anything that may come up."

So what changed? "They got married pretty young," says the close friend. "What kept them together for so long is [their 2-year-old son] Max." Aguilera says in a statement, "Although Jordan and I are separated, our commitment to Max remains as strong as ever." For now, Aguilera is leaning on longtime friends and keeping busy, recording new music for the soundtrack of Burlesque and performing at Justin Timberlake's charity concert Oct. 23. "It's sad, and she's hurting," says the source. "This is a hard transition for all of them."

  • Contributors:
  • Reporting by Ulrica Wihlborg/L.A.,
  • Jennifer Garcia/L.A..