There is so much to your story that I can relate to. My Kenneth was diagnosed as terminal with a life expectancy of less than a year, when he and I decided to get married. He spent 13 long years, beating the odds. During those 13 years, I raised 3 of his 4 children (one was an adult) and my two young children, practically alone. I spent more hours than I can count driving him to see just about every kind of specialist known to man, and we made so many trips to the hospital, I was on a first name basis with half the hospital staff at three different hospitals.
In the last five years of his life, Kenneth was in and out of the ICU, had surgery after surgery, and was literally losing himself one piece at a time through multiple amputations. I used to spend the night with him at the hospital, getting up every time he moved or needed anything. Then I would get out of the "bed" (aka the chair that passes for a bed in most hospitals) and drive two hours to spend the day teaching. As soon as school was out, I would drive by the house to check on the dogs and the kids, then return to the hospital for the rest of the night. I cannot tell you the guilt that I feel that my youngest son practically had to raise himself as a teenager, because his dad spent so much time in the hospital during his Sophomore - Senior years in high school.
In the last few months of his life, my Kenneth could not even roll over in the bed, without my help. He relied on me to feed him, bathe him, clothe him, take him to the bathroom, transfer him in and out of the wheelchair, etc. When you said, "I visited EVERY single day, I changed diapers, I dealt with every fluid known to man", my first thought was, "This was me!" I could also completely relate to what you said about being alone for so long, even before your husband died. The truth is, my Kenneth's illness took his mind from him long before it took his body, and I was alone for a very, very long time, even when he was right there in the room with me.
Though I have had my own significant health problems, both before and after Kenneth's death, I cannot even begin to imagine what you must have gone through, having to take care of your husband and your children, while facing your own cancer diagnosis and treatment. I am sorry you have had to face so much, and I hope you can find some peace and comfort here. (((Hugs)))