Aguilera, 29, and Bratman, 33, married in November 2005 in Napa Valley, California. At the time she told how he proposed to her in a hotel room filled with rose petals, balloons and gifts including poems he had written.
The couple have one son, Max, born in January 2008.
Separately, actors Courteney Cox and David Arquette said they had split on trial basis.
The Hollywood pair, who have a six-year-old daughter Coco, have "agreed to a trial separation that dates back for some time," they said in a statement.
"The reason for this separation is to better understand ourselves and the qualities we need in a partner and for our marriage," they said.
"We remain best friends and responsible parents to our daughter and we still love each other deeply. As we go through this process we are determined to use kindness and understanding to get through this together."
The pair have just worked together in "Scream 4," due for release in the United States in April 2011. Cox also stars in the TV series "Cougar Town," playing a newly divorced woman seeking to rebuild her love life.
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