Agreed Dreamer. Either lose the ego and sing (real live singing) in a lower key, or hang it up. Don't just lipsync or use autotune to try to keep going. If you are too proud to sing in a lower key, then taking the high road and retiring is the right move. If the rest of the guys in your band don't want to quit yet and you feel like letting them continue under a new singer, great. Or if your band existed in a prior incarnation before you came along, even though your era was more successful, they have every right to continue without you and your permission to continue with you.