Q. Is it right for a pastor to leave his unsupportive wife for another woman?
I do not see anything in Scripture that would endorse a pastor divorcing his wife because she did not support his calling.
If a man feels a calling to become a pastor and his wife does not support that, then he needs to wait until the two of them agree before he becomes a pastor. He can pray and talk things out with her, and hope and trust that if his calling is genuine, God will lead his wife to support it. God may very well be using the wife’s concerns to get the man to address important and necessary issues in his life. Once those issues are addressed, his wife may come to support his calling enthusiastically.
If a man has already become a pastor, and his wife does not support that, God may be using her concerns similarly to get him to address issues in his life or in his ministry. Pastors need to listen to all the ways in which God may be speaking to them.
Even if a pastor’s wife did not support him because she had turned away from the Lord, then as a good shepherd, he should leave the 99 sheep and go after the one that had gone astray. That is, he should set aside his pastoral duties for a time and give all of his attention to his wife’s spiritual condition. If she chooses definitively to leave his ministry and their marriage, then Scripture would say that he is “not bound in such circumstances.” He can let her leave, and conceivably he could remarry. But this should only happen after he has made every genuine effort to win her back to the Lord and to himself and their ministry.
But unfortunately, as you say, all too often pastors fail to hear how God is speaking to them, and they fail to give attention to the most important sheep in their flock. A wife may be unsupportive of a pastor’s ministry because he is not properly balancing work and family life. He may be neglecting his responsibilities and obligations to his family. In that case, the wife is not the problem. The pastor needs to hear what God is saying to him through her protests.
May God lead all married pastors to honor their marriages as the foundations of their ministries.