dudess.
I was raised by a step-mom, experience was some what less then pleasant.
Now when I look back at the whole thing I could not thank my step mom more for taking good care of my father.
Thing is, we are not bunch of individual living together. Our betterment(if that is a word) is mutual.
Your healthy hubby is going to live longer, and more pleasurable for your kids to be around.
I mean come on worst thing has already happened you are dead 
Let your kids live to best they could have under the circumstances.