I think that while an affair is a possibility, you should not rule out other reasons she may be choosing to be away from you. Perhaps she did not completely kick her drug addiction. Perhaps she is hiding the fact that she is back on painkillers, or something else. It does seem that she has moved out to hide some behavior from you, but it doesn't have to be an affair.
hi sara thanks for your post... i have actually thought about this and i must admit my wife has lost about 10 pounds in the 4 weeks we have been apart, nowthis could be through all the partying and booze, but she did lose weight rapidly last time she was taking the painkillers..... she only weighs about 8 stone as it is so this is not good for her health, but she choose it so its her bed to lie in.