Deenie you do need to know that this disease is not constant. There will be good days when your husband is connected and will act almost normal. There are other times when he will be completely confused and may not know who you are or what is going on at all. It is this up and down roller coaster ride that is emotionally and physically draining for you. Make the most of the up times to carry you through the not so good days. Also know that he would not act this way if his brain was not damaged. Dementia is much more than just memory loss. It is brain damage that affects every aspect of his being. So hold on to the good as much as you can. Keep your thoughts as positive as possible.
I highly recommend the book "Coping with Alzheimer's... A caregiver's Emotional Survival Guide" by Rose Oliver and Fances A Bock. There are lost of books that tell you how to take care of him... this one tells you how to take care of YOU! There are two people on this journey. His is important and you need to take care of him. BUt in order to take care of him you have to take care of yourself. To that end I do hope you have some help. Ask the grown children to give you a break. Just a trip to town can be refreshing. Let one stay with Dad and you go stay with the other for a good night's sleep. Or bring in an outside care giver for a few hours a week or a day. This is not a sprint but a marathon so you need to pace yourself and get the time you need for physical and emotional renewal