I teach students with learning disabilities. I have a nephew who is the same way. He is an engineer, highly intelligent, yet has difficulty managing money.
Is it possible for you to take total control of the finance situation? Explain to your husband that you love him, you know he is extremely intelligent, but that one of his weaknesses is in dealing with day-to-day financial issues. Tell him you know that your weakness is in being depressed at times but that one of your strengths is in organization. Maybe give him cash instead of a debit card. This isn't treating him like a child, it's accommodating a weakness (or disability if he has one). If he ends up spending his money early, you might have to sit down with him and plan exactly what to spend on a daily basis and how much extra he has to spend on the family. A lot of people who have ADHD have difficulty with this. It seems that your frustration comes from not knowing the source of the problem and not knowing how to solve it without treating him like a child. You must be in a difficult position, but I hope you and your husband can work this out. If you look up sites on adult ADHD (I don't know if this is what your husband has, but it will give you suggestions about helping someone like him) you might find help. Good luck to both of you!