The Collaborative International Dictionary
Bitheism \Bi"the*ism\, n. [Pref. bi- + theism.] Belief in the existence of two gods; dualism.
n. A form of dualism that recognizes two deity which are not in conflict or opposition (as good vs evil) but rather are in two exclusive forms or states (like male and female).
Usage examples of "bitheism".
He finally came to the conclusion that two gods exist, which is to say a bitheism, each contending against the other.
Although Valis Regained draws heavily on the bitheism of the Qumran people, it basically presents another view, not syntonic to Horselover Fat: monotheism, with the notion that evil has no true existence of its own but borrows its existence, or is lent its existence, from the one God.
After flirting with bitheism for years I have settled down to monotheism.