My sister has decided to leave her physically abusive, alcoholic husband. She doesn't have plans to divorce him and is hoping that eventually, he'll realize he needs help. She knows what a scriptural divorce is, and that this does not constitute remarriage. I don't think he will ever change, but it would not surprise me if he is unfaithful to her (she has no proof that he has been already) eventually. If he commits fornication while they are still married, but are not living together, and she remains faithful, would it then be a scriptural divorce? I know this seems like an attempt to weasel out of a bad marriage scripturally, but I'm afraid this is in the back of her unconscious mind and I want to know what to tell her should it become evident that she thinks this way.
While we make a distinction in our country between a separation and a divorce, the Bible does not. That is why you find expressions such as "put away," "depart," and "send away" instead of "divorce" in some translations. Since she is leaving her husband because of his abuse and alcoholism, the following passage applies:
"Now to the married I command, yet not I but the Lord: A wife is not to depart from her husband. But even if she does depart, let her remain unmarried or be reconciled to her husband. And a husband is not to divorce his wife" (I Corinthians 7:10-11).
What happens after the departure isn't under consideration. She cannot play a game of seeing who will give into temptation first and then claim the right to divorce and remarry. In fact, the verses prior in I Corinthians 7:1-9 explain why this is wrong. If the situation is severe enough to leave, then she should do so knowing she can only remarry her husband when he gets his problems taken care of. Even if he later commits adultery, she had already made her choice and that choice limits her options.