From the "God's Love" book (supposed to be studied with new converts,after finishing the "Bible Teach" book), pages 219-221:
In certain extreme situations,
some Christians have decided to separate from or divorce a marriage
mate even though that one has not committed sexual immorality. In such a
case, the Bible stipulates that the departing one “remain unmarried or
else be reconciled with” the mate. (1 Corinthians 7:11) Such a Christian is not free to pursue a third party with a view to remarriage. (Matthew 5:32) Consider here a few exceptional situations that some have viewed as a basis for separation.
Willful nonsupport. A
family may become destitute, lacking the basic essentials of life,
because the husband fails to provide for them, although being able to do
so. The Bible states: “If anyone does not provide for . . . members of
his household, he has disowned the faith and is worse than a person
without faith.” (1 Timothy 5:8)
If such a man refuses to change his ways, the wife would have to decide
whether she needs to protect her welfare and that of her children by
obtaining a legal separation. Of course, Christian elders should give
careful consideration to an accusation that a Christian refuses to
support his family. Refusal to care for one’s family may result in
disfellowshipping.
Extreme physical abuse. An
abusive spouse may act so violently that the abused mate’s health and
even life are in danger. If the abusive spouse is a Christian,
congregation elders should investigate the charges. Fits of anger and a
practice of violent behavior are grounds for disfellowshipping.—Galatians 5:19-21.
Absolute endangerment of spiritual life. A
spouse may constantly try to make it impossible for the mate to pursue
true worship or may even try to force that mate to break God’s commands
in some way. In such a case, the threatened mate would have to decide
whether the only way to “obey God as ruler rather than men” is to obtain
a legal separation.—Acts 5:29.
In all cases involving such
extreme situations as those just discussed, no one should put pressure
on the innocent mate either to separate or to stay with the other. While
spiritually mature friends and elders may offer support and Bible-based
counsel, they cannot know all the details of what goes on between a
husband and a wife. Only Jehovah can see that. Of course, a Christian
wife would not be honoring God or the marriage arrangement if she
exaggerated the seriousness of her domestic problems just to live
separately from her husband, or vice versa. Jehovah is aware of any
scheming behind a separation, no matter how one may try to hide it.
Indeed, “all things are naked and openly exposed to the eyes of the one
to whom we must give an account.” (Hebrews 4:13)
But if an extremely dangerous situation persists, no one should
criticize a Christian who, as a last resort, chooses to separate. In the
final analysis, “we will all stand before the judgment seat of God.”—Romans 14:10-12.