Hi,
I agree with Silly, many of us on this site would have similar experiences, where we really feel family & close friends have failed us. Personally I think it is the reality of thinking someone they know may die "before their time", which then brings their own mortality into focus... it's too much for some to cope with, as they are trapped into "living their life to the fullest, for material gain only".
It hurts and the hurt goes very deep, but nearly 10 yrs on, I just feel sorry for those who want to live their lives so superficially. My siblings have left the primary care of our ageing Mother to me, despite me having cancer 10yrs ago, and struggling health-wise for years after treatment. I realise my siblings have no comprehension of life during/after cancer, the permanent changes, struggles and hurdles. I just accept the hurt now, and move on... thanking God, I'm not so self absorbed!
Focus on your husband, kids & yourself as a family unit, accept help where it's offered and don't be afraid to ask people for help. Sometimes people just don't know how to help. Perhaps develop a roster and email it to close family & friends, asking if any can help. Simple things like collecting the kids from school, taking them to sports or even a weekly shop, can just take some pressure off, the super-hero, you've suddenly been asked to become. If they say no, then just accept it and move on.