Muslims (like other religion followers) said things which God did not say in the Quran, and adopted wrong interpretations.
What is said about beating the wife, only if she is impolite: going and coming and doing bad things, and she is - in this respect - disobedient to their husbands and lofty over his words. Such beating is not for the bed relations as many think.
So here is the interpretation of the Quran 4: 34
..الرِّجَالُ قَوَّامُونَ عَلَى النِّسَاء
The explanation:
(Men are the 'guides' of women, for that God has preferred some of them [the men] to the others [: the women], and for that they expend of their wealth.
Righteous women are therefore obedient, keeping loyal in the absence of their husbands, according to God's guarding.
As for those [women] from whom you fear rebellion,
admonish them,
desert them in bed
and beat them;
but if they submit to you, then do not seek a way against them; surely, God is All-High, All-Great.)
Such beating is not for the purpose of bed relation, but for disciplining. And this will be the last step before either the impolite wife reforms her conduct, or else the husband has the right to divorce her.
See that God tells the husband to desert them in bed as a way of disciplining.
What a man will do in case his wife is impolite: her conduct is bad and does not obey her husband?
The reason for revealing this aya of the Quran:
A man came to Prophet Mohammed - salam to him - and said: "My son in law, I gave him my daughter in marriage, and he started to beat her!"
The Prophet said to him: "Go and let her beat him as does he beat her."
The man has just left, and the Prophet called him: "Come, a revelation came to me by the angel: and he recited to him the aya which just I explained."
Which implies: no the wife has not to beat her husband, in case she is lofty over obeying his orders, and has a bad conduct.