Usher has filed for divorce from wife Tameka Foster Raymond. The R & B star filed the petition Friday in Superior Court in Atlanta, court records show. The couple, who got married in August 2007, have two sons together, Usher Raymond V, 18 months, and Naviyd, 6 months. Usher, 30, and his wife of nearly two years, 38, have been leading separate lives for months. The singer has been away from home often recording his next record in Las Vegas, one source says. "He's done his best to keep Tameka away," says the source. Another source told PEOPLE that Tameka has been focusing on keeping her family happy. The night before Usher filed for divorce, his wife was spotted at a screening of Eddie Murphy's new movie, Imagine That in Atlanta with the couple's eldest son, and two of her sons from her first husband. Tameka, who was wearing a gray shirt, tight jeans and high heels, "was happy and smiling," says an onlooker. The night his divorce papers were filed, Usher spent a low-key night at the Los Angeles club MyHouse. He arrived late and came in through the back then was seated at a table where he spent time with a few friends chatting and drinking. The singer, who was smiling and talkative, seemed to be in a good, but mellow mood. Calls to the singer's rep were not immediately returned.