Oh Lucky I am so sorry you find yourself in this impossible and heartbreaking situation.
I have no personal experience of caring for somebody (maybe I have all that to come....), but I am inclined to agree with your DD1 and others here, that now it's maybe the time for him to be in a home with round the clock care.
Of course I understand your DH's reluctance - fear even - to make such a move, but do you think it possible that some of his stress is borne of an innate understanding that the present situation simply cannot continue? And that he can see the impact it's having on your health and that worries him too?
It's a terrible decision for you to have to make Lucky, but I truly believe it will be better for both of you. The sheer relief for you, being able to sleep at night, being able to visit him and just relax with him, having your privacy back at home, will be immense.
Good luck whatever you decide 