I don't know how much this will help, beyond knowing that you're all not alone, but my DM has extremem bi-polarism. She's had it my whole life (I'm in my early 30s) and she's had it since she was 23 (for the last 34 years now). When she's not in a cycle, she has no recollection of anything that occurred. When she is in a cycle, she has no recollection of the way she "normally" behaves, which is completely opposite. Normally, she's calm, sweet, always wanting to help, a great person. When she's in a cycle, she is aggressive, foul mouth, etc. Like one of you posted, the police have had to take her in a number of times and know my family well as a result, and she's been in and out of facilities the entire time. For the last number of years, she was taken in and she never returned to her self. She's been institutionalized for all this time. It's never easy. It has never been easy.
But, I agree that you do have to think of yourself. As her daughter, I've often done what I can. But, I came to a point where in many ways, I have had to distance myself from her, because of what it kept doing to me. You do what you have to do, and don't let others make you feel guilty.
Also, for those who divorce someone who is mentally ill, I will never fault them for it. I have seen what my mom can do when she is in that state of mind and it is something that no spouse should ever have to endure, let alone for years upon years upon years. Please try to never fault someone who has to leave such a situation. I agree that one should hang in as long as they can, but do not agree that it's the same as sticking by someone with another type of illness, such as cancer. The level of abuse that loved ones endure when a bipolar person is in and even when they're out of those episodes is sometimes beyond explicable.
For those of you who are suffering with and for your loved suffering from mental illness, please remember that you're not alone. I also recommend that you find support to help.
One thing that mental illness has taught me is that above all, compassion on everyone's part is needed, as well as understanding. Nobody can ever truly know what they would feel and do in another person's shoes. Mental illness is horrific.
Thank you to the OP for starting this thread. It helped me to read that others understand, in a society that makes it difficult to discuss.