The Fatwa of The Shaykh (Click for larger image)

Islam is a religion that abrogates all previous religions, and it is the seal of religions as God says: "Whoso desired any other religion than Islam, that religion shall never be accepted from him, and in the next world he shall be among the lost"
(Ref: Chapter of Ale Imran, verse 85)

Baha’i as a creed [or a sect] is out of Islam and has nothing to do with Islam, rather it is contradicting and destroying whatever Islam has brought.

Knowing this, the International Islamic Fiqh Academy [Islamic Theology Council] of the Organization of Islamic Conference (Tunis is a member in the Academy and the organization), at its fourth meeting in Jeddah on 11th February 1988, decided that Baha’i is a disbelief in Islam and is aiming at undermining its doctrine, laws, and a way of life (the academy magazine, Issue no. 4, Volume 3, p.2189).

In the above context it is known that if one of the spouses is infidel or apostate, it obligates the separation. God said:" if ye ascertain that they are Believers, then send them not back to the Unbelievers. They are not lawful (wives) for the Unbelievers, nor are the (Unbelievers) lawful (husbands) for them."
(Ref: Chapter of Al-Mumtahina verse 10)

Inheritance between them is prohibited as well. Prophet Muhammad said: "No Inheritance between people of two different religious communities" (Narrated by Ahmed, Hakem, and Al-Nesaee). The majority of Muslim scholars concluded that what is meant by the two religious communities is Islam and Kufr.

Adding to this, there is disharmony between the spouses of contradicting beliefs, and this is proofed in this case shown to me. In her letter the wife reasserted what she is subjected to in terms of taunting, of continued coercion to embrace the husband’s creed (Baha’i), and of coercion attempts for her to follow the special rituals of this creed [sect] (like fasting for example; for the Baha’is it starts on march 2nd and ends on March 21st every year- which is the Persian feast of Nawrouz).