You can file a Petition for a Legal Separation. That allows for both of you to still be covered under the same insurance. You can try to get a durable medical power of attorney and durable financial power of attorney. However, given the contentiousness of the situation that you describe, that might only end up in litigation as well.
The information provided in this answer does not create an attorney-client relationship. If you are interested in his legal services, feel free to call Chris at (303) 409-7635 at his law office in the Denver Tech Center. All initial consultations are free of charge.
If you have not consulted with an attorney to discuss your options, you probably are at a point where you need to do this. The tragic part of your situation is that no one can control the actions of a mentally ill person who is acting out her illness for reasons only she understands. If she is truly not able to make rational decisions, you may wish to have a guardian or conservator appointed for her. A guardian can decide whether to pursue a dissolution of marriage and a conservator manages the protected person's funds.