Marriage is a serious event for a Christian. Gen 2:24 "Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh." Mark 10:9 Therefore what God has joined together, let no one separate."
Unfortunately, things can get sour between husband and wife. Divorce between Christian is even more serious as Jesus says “I say to you: whoever divorces his wife, except for sexual immorality, and marries another, commits adultery.” (Matthew 19:9 ESV)
Divorce for Christians thus becomes a taboo. Is there no way out?
Paul mention that “To the married I give this command (not I, but the Lord): A wife must not separate from her husband. But if she does, she must remain unmarried or else be reconciled to her husband. And a husband must not divorce his wife. To the rest I say this (I, not the Lord): If any brother has a wife who is not a believer and she is willing to live with him, he must not divorce her. And if a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him. For the unbelieving husband has been sanctified through his wife, and the unbelieving wife has been sanctified through her believing husband. Otherwise your children would be unclean, but as it is, they are holy. But if the unbeliever leaves, let it be so. The brother or the sister is not bound in such circumstances; God has called us to live in peace." (1 Cor 7:10-15)
This means that separation is allowed. It also means that divorce between Gentile and Christian is still possible.
However, that classification is not that easy to achieve. Paul said “The husband should give to his wife her conjugal rights, and likewise the wife to her husband. For the wife does not have authority over her own body, but the husband does. Likewise the husband does not have authority over his own body, but the wife does. Do not deprive one another, except perhaps by agreement for a limited time, that you may devote yourselves to prayer; but then come together again, so that Satan may not tempt you because of your lack of self-control.” (1 Corinthians 7:3–5 ESV)
Paul also mentioned that "But if anyone does not provide for his own, and especially for those of his household, he has denied the faith and is worse than an unbeliever. (1 Timothy 5:8). Therefore a Christian who does not care for his wife, he is as good as a Gentile.
Jesus said “If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother. But if he does not listen, take one or two others along with you, that every charge may be established by the evidence of two or three witnesses. If he refuses to listen to them, tell it to the church. And if he refuses to listen even to the church, let him be to you as a Gentile and a tax collector." (Matt 18:15-17)
In conclusion, if a husband does not care for his wife and does not treat her well, separation or divorce is still possible after mediation fails to turn back the one who erred. This also applies to the wife who does not treat the husband well. Paul said "Wives, submit to your husbands as to the Lord." Eph 5:22
Again this blog does not sanction divorce. It is only after all efforts to make the marriage good then it is accepted. Jesus said "Moses, because of the hardness of your hearts, permitted you to divorce your wives, but from the beginning it was not so" (Matthew 19:8).