Caring for husband with terminal brain cancer

I have been a caregiver to my husband who was diagnosed with terminal brain cancer a little over 2 years ago. We had been married under 2 years when he received this diagnosis. This disease is like 2 in 1....cancer and Alzheimers. I cannot leave him alone because of his confusion and forgetfulness. Also, his balance is off and at times falls. He cannot be left alone with the children often because he gets nasty, screaming at them as well as pushing. He is diabetic and sneaks food when I turn my back. I feel so trapped. I cannot work because of this, and we are living on SSD. He has become like a fourth child. This is so frustrating for our whole family. He has ruined whatever relationship he had with the kids. Also, whatever relationship we had is gone. I have become his nurse, not his wife. I feel so lonely at times. But most of all, I am overwhelmed, having to be in charge of everything in the house. My 11 yr old has ADD which comes with its own challenges. I try to handle all of these responsibilites but sometimes they get to be alot. I am doing the best I can for everyone while trying to go to school part time. Usually, I deal ok but once in a while the situation gets to me. I guess today is one of those times. Just needed to vent:)