It is a sinful act to beat any one, leave aside the wife who is your life partner who should get from you the best treatment. The Prophet (SAWA) said: Best of you are the best to their wives and I am the best to my wives.
Hadeeth states: I wonder from the man who beats his wife while he is more entitled to be beaten. (Biharul Anwaar, volume 103).
(Good believer never beats his wife) as the Hadeeth stated.
If a husband beats his wife and causes reddish ness on her body, he will responsible to a penalty called Diyah which increases with the degree of the beating.
That is apart from the punishment hereafter for beating.
'Real Muslim believes that his wife is a respected human being like him and will never beat her nor hurt her feelings.