i agree with @Esela. I am in a similar position with my husband he is cruel beyond belief. I have the cptsd and ocd he uses it to his advantage. he has told me i am a S**t mum who is unfit to look after children however he is very happy to leave them in my care for weeks when he is working away and when he is off out. he has told me that I have let other do things in the past not half as bad as what he has done and let them get off. Basically he blames me for his down falls. for years he has stormed of out for the day of even a few days blaming me and threatening to leave, however when I asked him to leave a few months ago he refused on the basis that he would be lonely, all his threats to leave before were rubbish he had no intention to ever go. He has gone outside of our marrage talking to women on chat sites and watching adult videos (all left for me to see) and blames me for this too likewise with his violence towards me (which has stopped now). It is rubbish and I dont buy a word of it now it is all about him knowing his actiona are wrong and rather than taking responsibilty casting blame. like you I do everything for the four girls and house myself with no backup from him or anyone else. same that I buffer things from him including my illness which he refuses to acknolwlege. It is like being single but with an adult there doing all he can to make life more difficult than it need be.
I am telling you this so you can see that his words are not about you but him. Some people believe that making other people miserable and blaming them will make their life happier (it doesnt) by keeping you down it keeps you in place, there for him. it sounds to me like my husband that in fact he is very dependant on you and scared that you will leave, they dont see that their behaviour is in fact more likely to make you leave. Be proud that you can raise your children alone many people cant so you are doing such a great job. you also sound like a really loving person to support him and try to protect him. I would maybe suggest that filter things (and i am telling myself this also) might not help in the long term as it stops them from having to look at themselves and deall with issues.
Would some sort of joint therapy be helpful if you would both agree to it?