What is the effect of anal contact with wives on Nikah. Does it break the Nikah? Please provide the answer with Hadith and in the light of Qur'an.

Praise be to Allah, the Lord of the World; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Having sex with one's wife in her anus does not make her Haram for her husband although this practice is a major sin. But, if this husband makes this practice a habit or his wife cannot prevent him from such a deed, then scholars of Islam have stated that separation becomes obligatory.
According to some scholars, this separation must be forever. However, we believe that if those couples repent, they are not to be prevented from return to married life.
As for an expiation of having sex with one's wife in her anus, one has to repent sincerely and do as much as one can of good deeds.
Allah Says (interpretation of meaning): {But whosoever repents after his crime and does righteous good deeds (by obeying Allâh), then verily, Allâh will pardon him (accept his repentance). Verily, Allâh is Oft­Forgiving, Most Merciful.}[5:39].
Allah knows best.