It's not the illness spouses are leaving, if they leave, it's untreated illness.
I just now read that in a blog (trying to look up statistics for you; many stressful situations increase divorce rates) and it makes total sense: http://natashatracy.com/mental-illness-issues/otherviews/leave-mental-illness/
No one expects anyone to stay with an abusive person, regardless of the cause of the abuse. Since he has been hurting you, you cannot take care of him. You are not required to help any adult who is hitting you.
Legal separation would give you some space and rights, a way to step back, and also to let your husband understand the results of his decision not to accept treatment. He said he wants to go to a group home. Trust him.
I know two couples in decades-long marriages where one spouse has serious mental illness and the other does not. The spouses with illness take medication, go to counseling, and understand that their illnesses require lifelong coping and treatment. That shows huge commitment and contribution to their respective marriages.
"Also can people share if possible their experiences with getting someone to accept their diagnosis or maybe hopeful stories of epiphany happening and dx accepted?" I would also like to hear these stories!