Scripture is clear that adultery & death are the only acts by which marriage may be broken. What then of abusive husbands? If they seperate they deny one or the other of relations and this is only allowed if agreed upon by the two for times of fasting (not due to beating). If they divorce is it acceptable in the sight of God?
Remember the passage in the old testament where the Israelites went out to destroy neighboring towns and a people of far away lands with worn out shoes, old bread and worn out wineskins came to them and made a pact with the Israelites. The Israelites agreed to the pact and gave their word to not attack or destroy them before ever consulting the elders or God Himself. Later on, they were out destroying other cities and came across the people they made a pact with. They were not of distant lands, but a neighbor. They were reminded of their pact and do you remember their response? It wasn't, "You lied to us so therefore our agreement is null and void", but it was, "out of fear of the Lord, they honored the agreement and did not destroy them...". (Joshua 9)
So, what is the proper biblical response to a man habitually beating his wife?