I only beat my wife once a week. That guy over there beats his every day! My wife should thank her lucky stars that she is not with that other guy and shouldn't complain.
Regarding what your wife should do about your beatings:
I need to know more about your wife and yourself to offer sound advice.
If your wife is capable enough, i would suggest that she leaves you. If, for any reason, that is not an option, i would need to know more about you. Are you likely to get angry at her for complaining, and beat her more often? If so, i would advise her against complaining unless she enjoys being beaten.