I think you already know what might happen, and are rightfully fearful of a downward turn. First thing you need to be concerned with is your safety and the safety of any children you might have in the house. Have an escape plan ready in the event he turns physically abusive and whatever you do, don't hesitate to call the police at the first sign of physical intimidation or any yelling or threats or throwing objects around. I lived for that **** for years with my own parents and that environment is hell. Do not stay with an abusive person. I don't care how long you've been married to him, he has no excuse to be abusive in any form.

ADHD is not the reason why he was physically and mentally abusive BTW-- that is something else entirely and a huge red flag that he has a lot more going on in his mind than just ADHD. These horrible dreams and crying every night is another indicator there is something very seriously wrong going untreated and possibly undiagnosed. Obviously he left these details out or refuses treatment for them. Is he possibly experiencing Post Traumatic Stress Disorder symptoms? Is he a trauma or a combat survivor? I would give him an ultimatum to see a psychotherapist if he chooses not to take medication. It sounds like he needs one really bad anyway because medication does not simply make problems disappear, it merely helps with symptom control. The larger problems you described here seem entirely unrelated to ADHD.

What was his stated reasoning for stopping the Stratterra?
It is unlikely the cause of his behavior since he has been taking it for 2 years, presumably without incident, unless there is something you are leaving out.