All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
We ask Allaah The Almighty to grant your husband guidance and to bring him back to the right path. The first thing we would advise you to do is supplicate Allaah for him; for Allaah has told that He responds to whomever supplicates Him saying (what means): {And when My servants ask you, [O Muhammad], concerning Me - indeed I am near. I respond to the invocation of the supplicant when he calls upon Me. So let them respond to Me [by obedience] and believe in Me that they may be [rightly] guided.}[Quran 2:186]
What is obligatory upon you is to find someone who can teach him and remove from his mind the doubts that may have afflicted him. There is nothing wrong if you do that yourself if you have Islamic knowledge so that he may realize the truth and adhere to it. If this happens, then praise be to Allaah; otherwise, he will be an apostate and you have to separate from him and not let him have sexual intercourse with you. If he comes back to Islam during your ‘Iddah (i.e. waiting period), you can return to him with the first marriage contract. For more details, kindly refer to Fatwa 90497.
In this case, it is not permissible for you to live with him in the same apartment because he is a stranger to you unless you are in a part of the house that has its independent entrance and utilities; then there is no blame on you. Anyway, it is more appropriate to be with your family to avoid the causes of temptation.
As for bipolar disorder, we came to know that it is a psychological illness. A psychological illness is not a legitimate excuse that removes husband's accountability for his actions as long as he does not reach insanity and thus he will be excused from all obligations and will not be held accountable for what he is saying. ‘Ali ibn Abi Taalib narrated that the Prophet, sallallaahu ‘alayhi wa sallam, said: “The pen is lifted from three (i.e., their deeds are not recorded): the sleeper until he awakes, the child until he grows up, and the insane until he regains his sanity.” [Abu Daawood]
Finally, he should refer his case to specialist doctors who will prescribe for him the drugs that may improve his condition so that this may enable him to have sound thinking and return to truth.
Allaah Knows best.