She's right you cannot use it as an excuse but you can show her through your actions that your attempt at making your life better with a disorder are honest and true. I am sure she will notice. When my W and I first separated she would occaisionally ask how my therapy or dr appointments went.
A good sign that she wanted to see some change and I got a compliment in a mostly 'negative foggy' email that it seemed my counseling was helping me express my feelings and communicate better.
Just keep showing her and your children that your problems with ADHD are improving and that the therapy you are getting is better than what you were getting.
Great job on quitting smoking. It's funny just how much a deal breaker it can be. My W used to be a horrible chain smoker and I dealt with it when I first moved in with her. I started showing some dissatisfaction about it and pushing my boundaries (at a time when I was good about that) on it and she decided to quit. I know she didn't do it for me because I think she was getting disgusted with the habit and wanted to do it for herself.
I did let her know that the smoking could have been a deal breaker and while that upset her greatly at first I think it really helped her stay steadfast with her decision. That was one of the most successful attempts of me establishing a boundary in any relationship.
Hard to believe I am in the boat I am now considering but a lot of it was because I started letting my boundaries slip soon after our marriage (There was a major family tragedy in our 1st yr of marriage that was the catalyst). But anyway you can show support by establishing boundaries believe it or not.
Speaking of that I am reading "No More Mr Nice Guy!" You can get it as an ebook download on ebooks.com btw. The 1st two chapters have been a rather sobering read. I hope you pick that one up. If you are anything like me having adult ADHD you probably have difficulty with co-dependency. It's a shame that some magic pill can't help solve the disorder but at least the symptoms can be treated and the behaviors can be turned around.