LeAnn Rimes' estranged husband is taking steps to make their split official. People.com says Dean Sheremet filed divorce papers in Los Angeles last Thursday. He's reportedly citing "irreconcilable differences" as his reason for seeking the divorce, which will bring an end to his marriage to the country star. Rimes and Sheremet separated earlier this year, and three months ago announced that they had agreed to move forward in dissolving their marriage. The pair tied the knot in February 2002. Their relationship began to unravel amid allegations that the singer was having an affair with actor Eddie Cibrian, her co-star in the Lifetime made-for-TV movie "Northern Lights." Over the summer Cibrian also filed for divorce from his wife.