I haven't read the other replies so if I repeat what others have said or go against anyone....sorry in advance.

The dog is stating, quite clearly, that it believes it has a right to be in the Alpha sleeping place and your wife does not. Either teach your wife to sleep in another room or remove ideas of grandeur from your dog's head - the dog needs to be comfortable, especially as it is getting on, a supportive bed outside the bedroom door would be appropriate - for the dog, not the wife!!