Lawson's exit from the house comes less than two weeks after the TV chef's hubby was pictured grabbing her by the throat, reported Sun Online.
Since then the 53-year-old has been seen without her wedding ring. Ad mogul Saatchi, 70, accepted a police caution for assault after the attack on her in a restaurant.
"It really does seem the end," a friend of the couple said.
Lawson, who has two children from her marriage to journalist John Diamond, who died in 2001, is off to the US soon to film a series as a judge in reality TV cooking show The Taste.