I also suggest that you google Non-violent Communication. There is also a book by that name. When we are able to word what we say in such a manner that the other person can hear it rather than become defensive we communicate much better.
Are you saying that although your husband says he has a job that allows him to work from home he is not responsible to anyone? He has no work goals to meet that are monitored by a supervisor? Is he essentially self-employed; perhaps a contractor?
Would it be possible to help him or encourage him to develop goals and strategize ways of meeting them? If he is actually working for someone, could he bring home information that you could go over together? Be a cheerleader sort of person instead of an unhappy wife. It's so easy to be discouraged by your husband's past failures and for him to respond by proving you right
I've seen books written about ways to work from home or how to run your own business. Would he read something like that?
I also suggest that it's extremely important for him to have a space dedicated as an office so that he's not distracted by the tv or children or anything else going on around him. And it's important to have a specific schedule of work times. One can be flexible with them but have to have a basic work schedule and plans for what they will do during that time.
It will take him time to develop a plan and it is important for you to be encouraging and not a nag. I know that a positive atmosphere is very difficult to provide and maintain especially when he's tried and failed before. I can hear your frustration.
The two of you need to talk with each other and decide together on some boundaries for ways that will make this more likely to work for you. The first rule that I'd insist on is that you will continue with the household routine that you've set up and that works for you. This means that the kids bedtimes are the same. Meals are the same unless you agree to a different arrangement. Taking care of your home is your job and you also need to have goals and plans for reaching them. I would include in my list of needs that if he's going to be in the main part of the house he's to help rather than be a distraction.
Perhaps you could make some compromises such as he agrees to watch the kids while you go shopping. The two of you make a schedule for getting household chores accomplished.
Perhaps it's time for some couples counseling. Definitely time to work together on finding ways to communicate with each other. Time to find ways to destress and manage feelings without blaming or being cranky with the other one. Physical exercise does help us destress. Getting away from the house and doing something in which you have fun. Perhaps the two of you could each designate one specific period of time to be only each one's period of time to do what you want.
I know how very difficult it is to be calm, non-judgmental, and supportive. My mother was always critical of my father's plans but her comments and attitude did not change his mind about doing them and made being at home unpleasant much of the time. Some husbands blame their spouse for their failure saying if you had been more supportive, etc. I could've done this. My father never blamed my mother. However, I could see that he might have been more successful if she'd been more supportive. We would have definitely had a happier family even if my father was not a greater success.
Did he change jobs so that he could work at home? Or was he unemployed? There are so many variables that would change the way I'd approach him after "digesting" the decision. The one constant for me is to find a way to be positive in what I said and to not express criticism. One technique for helping with this is to always use "I" statements. You've stated one example. "I'm going insane." Ask him for his help with the way things are so that you can feel sane again.