Anemones will split for two reasons -- if they are happy and healthy, or if they are stressed and think they are going to die. If they are stressed, then splitting doubles their chances of survival. If yours is bleached, it likely split due to stress. Why is it bleached and unhealthy? What are your water parameters? What kind of lighting do you have? It can be very difficult to bring a sick anemone back to health if your water quality and lighting aren't top notch.