From `Abdul`Aziz ibn `Abdullah Ibn Baz to the Muslim brother who is is keen to protect his religious commitment and honor, may Allah keep him safe, Amen.
A ssalamu `alaykum warahmatullah wabarakatuh (May Allah's Peace, Mercy, and Blessings be upon you!):
I have read your question regarding the wife that tells of her husband having cursed Islam and the Lord...etc.
Cursing Islam and the Lord (Glorified and Exalted be He) is one of the most grievous types of Kufr (disbelief) according to the consensus of the people of knowledge. As for proving this against the man, issuing a sentence, and separating him from his wife, this is to be judged by the court.
I ask Allah to guide us all to what pleases Him. Assalamu `alaykum warahmatullah wabarakatuh (May Allah's Peace, Mercy, and Blessings be upon you!)