The actress separated from James in March in the wake of his cheating scandal. The split came just 10 days after Bullock won the best actress Oscar for her role in the blockbuster "The Blind Side."
Bullock and James, 41, started the adoption process four years ago and brought Louis home in January but decided to keep the news to themselves until after the Oscars. The boy was born in New Orleans.
Bullock told the magazine that she is "sad" and "scared" about divorcing her husband of five years.
James reportedly confessed to Bullock that he had been unfaithful with at least seven women. He also issued a public apology to his family following the reports of his infidelity.
Bullock's reps would not say in what jurisdiction the divorce papers were filed.
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