Hi again,
I'm sorry I misread your original post, I am tired. I may be mis-reading again, but it seems to me then that your husband has been able to be a big earner and enjoy the benefits of family life, because you are working part-time and deal with the day to day aspects of having children. (This is without even considering the health aspects - I have a mental health and fatigue related condition and one of my children I am currently trying to get evaluated for ASD, so I speak with some experience of the difficulties there, but not as much as you). You should be more than proud.
And, not only that, but your finances beyond house and bills are separate, which means what? He has his pension, you have yours; he has his savings, you have yours etc. Has he ring-fenced his earnings in his will too? What happens if he keels over tomorrow? Are you and the children provided for?
You are going to work FT, despite the fact that you probably actually need rest for the good of your health and wellbeing and between you, your household has enough money; and the fact that you are worrying how you will cope suggests that right now, the additional pressure may actually be more detrimental to your health.
I get wanting to be independent, but what does this mean exactly? Paying more to the household, when there is already enough? Building your own nest egg (running away fund). For me, I need to work FT as I am a single parent, but I also know, from my lovely therapist and the occupational health person I ended up seeing, that my health is a priority, otherwise then I can't do anything for anyone. Does that make sense? Your children are better off with a mother who can work part-time and meet their needs (which you are doing) than one who wishes to prove she is tough as nails. Prove to who?
FWIW, I suspect that this man leaving you and then coming back has left you with a fear that he will do it again; and in the meantime, he has done a number on your self-esteem, but that is reading maybe too much into things - but think about it.
Don't mix up being independent and strong with doing everything, and that is not really a long term recipe for health and wellbeing. Apologies for the long post, but honestly, you don't want to get to the stage where you are mentally and physically exhausted as well as ill; and your husband should not be letting that happen or encouraging it.