ADHD and financial problems in marriage

I have been married to a man with ADHD for 15 years and I can't count the number of new projects he has started only to fail completely after a few months. The problem is that it is always the same project. My husband keeps trying to set up magazines where he is the editor. He gets his friends to write free articles and then after a few issues he has no money to publish anymore and its closes. At the same time, he has about three free websites he has created that he writes endless articles for-but with no income. Our son is now 17 years old and it is critical that I save money for university for him. I can no longer afford for my husband to pursue these endless self-publications and I have told him that it is absolutely finished now. I pay all the rent, the insurances, the school fees, have bought him a car, etc. In other words, my husband has a total free ride claiming that he needs to invest in his future by pursuing his writing (he is 65) and therefore can't work. I have just found out that despite my absolute insistence against it, he is launching yet another new magazine with a tiny investment that won't allow him to get paid but will cover the cost of the publishing of the first issue. He insists that this is a pilot and it is critical that he do it because he has already told everyone he is starting a new magazine. I am at the end of my rope. It is financially killing me, but on top of it I cannot stand going through another cycle of big idea, launch with a fraction of the required money, months of trying to get more investors, then failure and another closure. Throughout this entire time, he earns not a penny and I have to cover all the costs of running our home. I am 53 and will not be able to save for my own retirement because of his lack of financial support. Evidently there is nothing I can do to force him to work but is there some way I can get him to stop with all these endless new projects (which are always just a variation of the same idea)? I can't bear it anymore. I have begged him not to do this again but he absolutely won't listen. I want to cut him off financially but am not sure if I can legally do this. Where can I get help? I can't stand another year of living through this..