The 44-year-old celebrity chef revealed on Facebook this evening that they did not arrive at that decision in haste, reported E! Online.
"After an amicable separation since July, Todd and I have decided to end our marriage. Although our decision to separate comes with a great deal of sadness, our focus on the future and overwhelming desire for our family's happiness has given us the strength to move forward on separate, yet always connected paths," she wrote.
Thompson and De Laurentiis, who hosts TV cookery show 'Giada at Home', have a six-year-old daughter, Jade Marie De Laurentiis-Thompson, together.
It is not certain whether they have filed for divorce. The duo married on May 25, 2003.