Megan Fox and Brian Austin Green ''rarely shared a bed.''

The 29-year-old actress recently filed for divorce from the former 'Beverly Hills 90210' star, but ''no one is surprised that they've split.''

A source said: ''They rarely shared a bed,and when they did, there was zero passion.''

The 42-year-old actor, who has sons Noah, two, and Bodhi, 18 months, with the brunette beauty, also grew tired of her busy film schedule, as he spent much of the last few months being a stay-at-home dad.

The insider told America's OK! magazine: ''Megan's schedule frustrated Brian. She was never around. But for her, work was a fun distraction. She loves being on set so much that she stopped thinking about Brian.''

The 'Teenage Mutant Ninja Turtles' star confessed last year that she and Brian rarely got to spend any time alone together.

She said: ''Brian doesn't get any intimacy whatsoever.''

But she also insisted she worked less than 20 days a year in order to be with their family.

She said: ''I have to make one movie a year because I have to invest in their future and I have to be able to pay their way through college and be able to provide for them. I'm looking for movies that will shoot in Los Angeles, for projects where I'm part of an ensemble so I can shoot in and out in 10-20 days. It's all about trying to spend as little time away from my kids as possible.''