How should I deal with my righteous wife who is overcome by religious bigotry?

Praise be to Allah for a righteous wife, for she is the best provision of this world. If your wife's "fanaticism" is adherence to religious principles, such as her commitment to the hijab and avoiding mixing with men, then this is not fanaticism but rather a praiseworthy adherence to religion. However, if it is extremism and rigidity that affects your rights and the rights of your children, then you must be patient and guide her gently to fulfill her duties.