What makes this problem so difficult is that your husband refuses to get help since he clearly needs it. While he suffered with ADHD practically his whole life, it is also clear that he has never learned how to communicate effectively and seemingly may never have learned basic life management skills. The problem with getting a diagnosis of ADHD and only taking medication to treat it is that some people never learn how to change the ADHD behavior and become reliant on the medication as a method of coping, which does not always work effectively.
I also wonder about why he has stopped the medication now. Why has this happened? What has provoked or precipitated this? Did he stop his medication and then all of the other issues began or was it the other way around? It may be instructive for you to try and pinpoint how and when his unusual behavior began.
You have a few options in this situation. One option may be that you ask him to go to marriage counseling with you. Maybe if you offered to go with him he may be more willing to see a therapist if he felt that it is a combined problem solving effort with both partners working to resolve the issues. A second option may be that you consider seeing a therapist for individual counseling. I see this option as being necessary for you, especially if he adamantly refuses to go to get help for himself. You’ll need guidance and assistance, much more than I can offer over the Internet, about what next steps are needed to correct this problem and save this relationship.
Lastly, if he is completely unwilling to seek help and these problems continue unabated, you may need to consider separation or divorce. Hopefully, it will not come to a separation or a divorce but if your husband is unwilling to get help, and continues his disruptive behavior, it may be your only option. Marriage or individual counseling is the best place to start resolving this problem. Thanks for writing. Take care.