Didn't Ben leave after the album "Fallen"? I found this part at WiKi:

Terry Balsamo from Cold joined the band, replacing Moody.[11] Lee has recently stated in interviews that she was abused, physically and emotionally, by Ben Moody in a previous relationship and regrets trying to stay friends with him for the sake of the band after they broke up.[12][13] Moody confessed in an interview that not only does he suffer from bipolar disorder, but that he's kicked a drug and alcohol habit that he was entrenched in during the strife within Evanescence.