Cursing Islam is considered an act of Riddah (apostasy). Such a person is required to make Tawbah (repentance to Allah). If he repents there is no harm on him; otherwise he will be killed for Riddah. It is not permissible for his wife to stay with him until he has made sincere Tawbah to Allah (Exalted be He). May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.