I was a caregiver before I became a patient. I also did my best to emotionally support my sister when she became our Mom's caregiver.
The very most important aspect of this situation you have to come to terms with is this: You can't fix it.
You can take care of him, you can do your very best to help him through this, but in the end, you simply can't fix it. Nor should you try. From the little you posted, it sounds like you are doing the right things. Throughout the years I was caring for emotionally disturbed son and a seriously depressed wife, I kept wondering what I was doing wrong. My sister did the same thing and three years after Mom died, she wonders the same thing.
When we provide care for someone we love, it is hard work. When things don't seem to improve it can be downright scary. Not to mention depressing. So, take heart and accept it that you likely aren't doing anything wrong.
And then make sure you are taking care of yourself. It is very easy for caregiver to forget to do that, or to feel it should be the last thing you do. The simple fact is, if you don't take care of yourself, you can't take care of anyone else.
There were times that I resented what my son was doing to the family. Your resentment is normal. Your life has changed, things are not easy and perhaps you wonder what the future holds. Acknowledging your honest feelings is the first step towards dealing with them constructively since no one really wants to live in resentment of their spouse. Understand why you feel the way you do, take good care of yourself, and take care of your husband...as needed. One of the best things my wife has done for me has been to stay out of my way and allow me to fend more and more for myself.
I can sympathize with your husband's problems eating and talking. I can't generally swallow without drinking, if I bend over after eating the food will come right out of my stomach, and a number of other problems. Until recently I had been spared the pain of headaches. I'm not an attorney, but I do have to speak a lot in my job at length...I thought I was going to pass out from hypoxia this morning. So I have some idea of what he is going through.
I hope this is helpful in some way, but more, I hope you are taking good care of yourself.
-Tod