On the question of what constitutes a criminal sin: child abuse. Physical abuse. [S-x]ual abuse. Drug abuse. Theft, and so on. On the question of what is legal in the eyes of man but not in the eyes of God: abortion. [S-x]ual immorality, and the like.
On the question of where to draw the line between annoying, insufferable, heartbreaking; and criminal: if the husband is withholding provision for groceries — this is no joke, I knew a woman in this instance — why is he withholding it? In this woman’s case, her husband was a poor money manager, and never budgeted for groceries, nor would he accept his wife’s help in managing their finances. She had to daily scrounge the cupboards to find food to feed the children during the day. Usually when the suppers became lean — in other words, when his meals suffered — the husband would find a way to bring a few bags of groceries home with him. This was frustrating as all get out for the wife, but the children never failed to grow or gain weight, due to the wife’s creativity and economy, in which the Lord helped her. If the food was so scarce that the children failed to thrive, then that is child abuse.
But I think in most specific cases of the question, “Where is the line between heartbreaking and criminal?”, it would be best for the wife to ask the Lord honestly; I do not think He would fail to answer her, if she listened honestly, and to discuss the matter with her pastor and elders. She would need wise counsel.
My concern with today’s born-again Christians, is that 66% of them do not even think that it is wrong to divorce for another reason than adultery. This easy divorce mentality, Jesus said, is due to hardness of heart. A heart where love has grown cold. Most people will not tolerate dying to themselves in order to love another sacrificially, and that is what we are talking about when we talk of bearing with each other, of living in grace with each other, of enduring personal suffering for the sake of righteousness. Of learning the attitude, what can I do today to show my spouse that I love him, rather than the attitude, what has my spouse not done today to show me that he loves me. Of learning patience, of learning to find joy and contentment in life through the Lord alone, if necessary. In Paul’s day, many Christians were slaves, and Paul said to them, be content where you are (although take your freedom, if the opportunity arises).
The answer of do not divorce, and endure patiently under suffering, is not a popular answer. Today we live in a climate where it is socially acceptable to divorce — even in the Church. It is a horrible state of affairs that the Church disciples believers so poorly that Christians exist who do not repent of sin. The Church makes things worse for the wife (or anyone, really) by not obeying the Scripture in Matthew 18. But if the wife desires to obey the word of God and not divorce; if she desires to honor Christ as Lord in her heart, she can, and the Lord will be her portion; even if her husband does not obey the word, and even if the Church does not obey the word.
“Blessed are those who hunger and thirst for righteousness, for they will be satisfied.” Matthew 5:6