As a former higher rate tax payer who now works part-time, I did not begrude paying taxes because I knew that compared to my lower paid siblings, I was still better off than them despite losing so much of my gross income to tax.
I think OP opening statement was unreasonable. However, I understand her fustrations and imho, she needs to seriously re-evaluate her life. Having a disabled DH does not mean that you have to work over 100 hours a week to compensate for his lack of income unless you are doing so to avoid being at home.
You say he had an accident so I am assuming that you received some sort of financial compensation? In addition, why are you not claiming the disability benefits for your DH? After all, I'm sure you accept child benefits?
You say that your parents care for your DH and children and if I have read it correctly, they live with you - I'm assuming they are retired so won't they be receiving pensions? If they are not retired, won't they receive benefits too?
I think you need to change your mindset from "woe is me" to "what can I do to make my life easier".
Also I would just like to say that in most cases, people choose to work excessive hours - I use to do it and convinced myself it was obligatory and compulsory. Rubbish. I was a slave to the work place and thankfully, becoming a mother made me realised that life was about living, not working.
Finally, as a tithe payer to your church, you will know that it is easier for a camel to go through the eye of a needle than for a man to enter the kingdom of God. Also, it should not be loss on you that the first of the 10 commandments states "You shall have no other gods before Me". Consumerism and the shallow worship of money/material goods is a blight on modern society. That is why I have trouble reconciling you being a tithe payer and bemoaning your social as well as moral responsibility.