The 70-year-old art collector spoke out for a second time following the confrontation with his TV cook spouse, which he has dismissed as "a playful tiff".
He told London's Evening Standard: "Although Nigella made no complaint, I volunteered to go to Charing Cross station and take a police caution after a discussion with my lawyer because I thought it was better than the alternative of this hanging over all of us for months."
Saatchi accepted the caution after visiting the police station yesterday. In a statement, the Metropolitan Police refused to name him, but said: "This afternoon, Monday June 17, a 70-year-old man voluntarily attended a central London police station and accepted a caution for assault."
Former advertising executive Saatchi said he was holding Nigella by the neck "to emphasise my point" as they discussed their children. But he admitted that the pictures, in which his wife appears to be grimacing as he holds her outside Scott's in Mayfair, looked "horrific".
He told the Evening Standard: "About a week ago, we were sitting outside a restaurant having an intense debate about the children, and I held Nigella's neck repeatedly while attempting to emphasise my point.
"There was no grip, it was a playful tiff. The pictures are horrific but give a far more drastic and violent impression of what took place. Nigella's tears were because we both hate arguing, not because she had been hurt.
"We had made up by the time we were home. The paparazzi were congregated outside our house after the story broke yesterday morning, so I told Nigella to take the kids off till the dust settled."
A spokesman for Nigella confirmed she left the family home, in a multimillion-pound converted factory, with her son on Sunday, but refused to say whether it was a temporary or permanent move.