1 Corinthians 7:10-11 gives guidance concerning the terrible scenario presented in this question. Paul tells married Christians that they should not separate from each other (v. 10). However, he then acknowledges that separation may occur anyway; should that be the case, the separated spouse should remain unmarried or else be reconciled to their estranged spouse.
While it is true that it is not God’s will that anyone should separate those whom He has joined together in marriage (Matt. 19:6), we can conclude from the Corinthians directive that it is also true that He does not wish harm to come upon a sister in Christ who is being treated with violence by her husband.
Thus He allows the option of separation under the parameters of remaining celibate or being reconciled should she determine it safe to return to her husband. Should her husband commit fornication against her, there would also be the option of divorce and remarriage (Matt. 19:9).