How to stop stepkids and husband from sucking the life out of me.?

Ive raised my step kids since they were 3&7,now 10&14.I have shared guardianship papers with court.I provided for them,rearranged work schedule,doctors,school etc.Provided and loved as my own.We have them every other week,sometimes weeks at a time.Most of my pay went to them.I became extremely ill last year from rare disorder and had to retire early. I have a 21 yr old and my spouse have a 2 yr old.Im expected to clean,,cook and care for the children when they are here, father is sleeping, works nights, that's fine.They are a joy,we had fun,but when they were not allowed to get their way(safety reasons, money, or i was sick)i was treated awful.Now, they don't listen, they yell at me,or cause my daughter harm,or yell and fight each other, i try to stop it,they wake their dad up & start making up stuff &wine to their dad, he starts calling me names, yelling at me.I hate to even say this, it hurts.They've lied on me to get their way with the other parents,played one against the other taught my 2 yr old curse words,hit her a few times, yell at her for crying, when i say something or try to give them a time out, they wake their dad up saying a bunch of lies then all three of them starts yelling at me!Ive went without food ,baths,basic Hygiene stuff because their dad gives them everything they want and himself what he wants most of the time,when they get something they just toss it, in meantime im doing without some of my medications, doctors visits. husband will only do things with kids. i medically cannot drive but im not dead and still young, i do what i can, I feel used by them,ive given money to their mom to help her out with so many things,(a christian southern gal) just because i thought it was the right thing to do..I keep giving into my husbands demands but i think dog pee is treated better than this.I believe in my vows, want to continue to love and cherish my family, but im getting a bad taste in my mouth now and beginning to get fed up with being expected to be someones maid while everyone tears up our home, treats me badly, oh yes, spouse even throws items of mine away without asking, important expensive stuff of mine , he doesn't even care when i say something. Ive talked, cried pleated begged tried to change everything i do, but the only thing that's changed is that im not the smiling, happy, girl anymore.I love them, but its affecting my health so bad and preventing me from doing things with the 2 yr old that i want to be doing.We've went to dinner twice since our honeymoon in 2007, hes had an affair in 2008and put us in bankruptcy. He isn't having an affair now,but maybe hes cloned me into a pushover and broke my spine. When i talk with him about it and make suggestions or let him make suggestions he tells m e everything is my fault and none of them do anything wrong. He left me unconscious twice on the floor few years ago , mom ended up getting me.Kind of scary.But he had an excuse or made it sound like i didn't know what i was talking about that he had to quickly care for the 2 yr old, i vaguely remember trying to crawl on porch and pressing my alarm button, that's when my mom came and i ended up in hospital for a few weeks. Now what. Please no negative comments unless its constructive criticism.I feel bad enough about speaking this loudly, this is my first time ever. Thanks,