Hi Wendy,
Sorry that you have such bad news, and now to some extent have to learn a new way of living. The time of diagnosis is a huge shock for everyone who has to come face to face with cancer, it will take time to come to terms with living with cancer and adjust to the many possible changes that cancer brings with it.
Your husband is very young, and I am guessing that you are too.
No one can answer the question 'why?' there is no answer, no 'why'. It just 'is' unfortunately.
Your husband has nsclc 3b you say, well there is a small ray of light there, in that it's not as bad as it could be, and it's been discovered relatively early for lung cancer. How was it discovered, did your husband have any symptoms? How is his health aside from the cancer?
I suggest you research as much as possible to learn about the disease and what to expect and the treatments, this way you will be better able to ask the medical team questions and understand if they start talking in jargon. There are lots of good informative sites online, most of them are American and connected with cancer institutes, they go into more depth then the British sites.
The people on this board are very supportive and in similar situations to you, most of them have far more information than I can offer you as far as caring for your husband.
I have stage IV cancer of unknown primary which has metastasised into the lung which is why I am on this board.
Don't panic, you are in shock right now, it will pass, then you will be in a calmer place to move forward with your husband and 16 year old daughter or son?
God bless you and your family
Cee