Gwyneth Paltrow and Chris Martin's marital problems have been brewing for a long time.

Several friends told People magazine that the pair had an "open" relationship at times during their decade-long marriage.

"They have been on and off for many years -- the marriage was falling apart," a close friend of Paltrow's told the magazine.

Added another insider: "They were physically separated and emotionally."

On March 25, the 41-year-old actress and 37-year-old Coldplay frontman announced their plans to separate.

"It is with hearts full of sadness that we have decided to separate," they wrote on Paltrow's website, Goop.com, in a post titled "Conscious Uncoupling." "We have been working hard for well over a year, some of it together, some of it separated, to see what might have been possible between us, and we have come to the conclusion that while we love each other very much we will remain separate."

Meanwhile, post-split announcement, the couple was spotted vacationing with children Apple, 9, and Moses, 7, in the Bahamas.

According to People, distance as well as differences in their personalities (Martin "is the kind of person who is always in a T-shirt" while Paltrow's "much more glam," said a pal) prompted the breakup.

According to Us Weekly, the two disagreed on how to parent their children. Paltrow's "strict diet rules" reportedly was another area of strain.