Can a caregiver divorce a dementia person?

having tried divorce, 2 times previously, before his illnesses, because of verbal and emotional abuse over a large number of years, the spouse now has vascular dementia, exasperated because of refusal to take care of his self, He has diabetes, had open heart surgery, stage 4 prostrate cancer matasized, having 3 strokes with seizures, and numerous other life threatening health issues.He is on numerous meds too. He always has been a jeckel and hyde person, sweet to others, and a monster to me his spouse, now he is still the same only magnified 100 fold, the ongoing disrespect is very difficult, as a caregiver to deal with. and now that he is unable to regain his former life, I am this awful controlling person (who however, sees to it all the bills are paid, the food is in the house and cooked, laundry etc. all taken care of for him)....the thought of going on the remaining few years I may have, living this way is enough to make me want to divorce him so I can perhaps have a bit of solice the rest of my days.Before my health goes down. Any suggestions?