As the other replies said, it is very important to talk to his doctor & learn about dementia.
Do you ever get a break from being around your husband? In these types of situations, even though you know he can't help it, it is really beneficial for your health, physically and mentally, to be able to "get away" on a REGULAR basis. Sometimes, retired folks are kind of 'stuck in the house all day' with each other, and that contributes to the frustration.
Other than getting away from the house, maybe having visitors might help, too.
Please don't hesitate to ask others for help. There might be someone in your neighborhood, who would love to visit with you, to sit with your hubby while you take a break, or to take you out to lunch.
Good Luck to you!