My partner was diagnosed with incurable cancer in November after twisting his leg and breaking his hip. He received a hip replacement and immediate radiotherapy. As the cancer had spread from his prostate into his hip bone, up his spine and into his ribs. He has four tumours on his spine one extremely close to his spinal cord. 
He had his first round of Chemo at the beginning of January and caught an infection his second round was delayed and he received it this week - today he is very down. I don't how to help. I went back to studying last year and working a  full day a week. I'm really trying (I think) to do what I can for him. I'm so tired and feel so frustrated because on the bad days ( and there have been a few) I feel it never ends. I have tried suggesting endless things to do if he is feeling up to it but he gets increasingly angry at me. Everyone always asks how he is - I just feel overwhelmed- but feel so selfish. Lately I escape to the bathroom just to have a cry because I feel it's wrong of me to have this need when I'm fit and healthy. Anyone felt or feeling similar? Suggestions to help me put this in context and not think this is about me please because I know it's so wrong.