Oh boy... You too have one of those ??
Been throught it with mine and while he had gotten better since the surgery and since Chemo started he still has his moments and relapses...
All I can say hang in there. Find the strength to sit him.down and talk to him honestly about both how his bad behabiour affects you and about how you feel physically and emotionally.
Mine did admit when I had a meldown few weeks into my initial chemo that he did not think I was really unwell as I did not look sick - and that feankly was my own fault as I pushed myself past human limits to try and be 'normal'. And as already suggested above maybe going with him to your GP to have the GP help explain the difficulties you have to deal with would help.
I hope you do not have to go through all the pain I went through with my husband but what did end up getting him to cooperate in the end is my basically spelling out and making him write down what his duties were - literaly writing down chores he would have to do and frequency and simply ordering him that from now on if I am in the Emergency he will stay by my side regardless of how late or long I am there (instead of going home to rest up) and when I am admitted he has to make the food at home to ensure I have food when discharged and what time he would have come by to be there in time for me to be discharged.
It may sound mean and extreme but I had to make that a condition of him staying in the home. Yes he has been an arse and he regrets it afterwards and is all appologetic but it does not help when I am ill and weak and suffering consequences of his irresponsible behavioir.
You have to remmeber you have to think of you so you can get better. If you are not putting yourself first there will be no way you can take care of anyone else (including your children) so sit down, if need be write down what you need from him. Spell it out and if you need to get a 3rd party to help you get the message across then get them involved.
GPs can help, family and friends can help and also the Cancer Centre or the breast care nurse or the Oncologist can put you in touch with Psychologists who can help. Both you and him can get counselling and maybe that is exactly what he needs - a 3rd party sitting him down and getting him to understand what you are going through and what he needs to do for you as if he cannot steo up then you need help to figure out where you can get that support.
Hugs
Jel.