I never took Usher for one of those guys that falls for a girl and loses sight of all that's important to him. The six-packed star has always been a Mama's Boy, keeping his mom on as his manager even when he made it big. Enter the fiancee, Tameka Foster, a stylist that left her hubby after, ahem, working with Usher. Sources say that the Mrs.-to-be- is encouraging her man to get rid of his mom, Jonetta, as manager and let his new lady take over. Seems there's a little tug-of-war going on for the man's affections. "They definitely don't get along," a spy tells the Daily News. "Tameka came to Jonetta's birthday on April 6. They hugged and posed for photos, but it was all for the cameras." Before they were dating, and Tameka was just "working" for the singer, Jonetta encouraged her son to fire the stylist. Tam then went on the radio and said some not-so-nice about her future mom-in-law. "Tameka has a hold over him," says one friend. "Nobody can figure it out." Mother's Day might not be all flowers and candy this year.