How do I convince my wife to get tested for ADHD?

    I have ADHD which was diagnosed when I was a child. I didn't start medicating until I was 30. Which completely turn my life around.  I am now 42  and I manage my ADHD.  I met my wife nine years ago. She is a highly creative whirlwind of an artist.   Part of the reason why I think we work so well is because I excepted her eccentricity. I think she felt loved unconditionally.   Our marriage  is now all but over. We are living apart, and have been for six months.  A week ago  we finally managed to sit down with a marriage counselor. 10 minutes into the appointment the marriage counselor asked my wife if she was ADD.  She immediately dismissed the idea because she was tested as a child and they concluded she was not. Then we talked about how that was my issue and not hers.  Later that day I began to think about it. She  fidgets  and can't sit still.  She constantly forgets to do simple tasks she's promised to do. There is a room in a house that my wife has dumped all of her things, it's a huge mess. I tried to get her to clean it up for over 3 years. She's too overwhelmed by it to handle it and she won't let me take care of it. She has a lot of trouble starting projects and she often doesn't meet deadlines.I own a business that she has done a lot of design and photography for. Her lateness with most of projects and disorganization  constantly put me in the middle negotiating between her some of my employees my business partner. Though her work is very good, her reliable inability to meet deadlines is a major problem.  We would not rehire anybody who was this unreliable, and we only continued to work with her  because she is my wife. As you can imagine this had put a lot of stress on a marriage. Then nearly 2 years ago she dropped the bomb. She told me she changed her mind and she does not want to have children.  All of the reasons she gave about not wanting children had a common theme. The idea was too overwhelming. Our house is too chaotic, the neighborhood is too unsafe, our future is  too uncertain. Her ADHD is so obvious to me now I can't believe I could not see it for nine years. I am ADHD,  and I have been  hoping with it all of my life. I run and arts program for children. I have spotted ADHD in many kids and talked their parents into getting them treatment.  As an ADHD person working with ADHD kids I been able to mentor them wih compassion, empathy and patience.  I feel so incredibly stupid that it in a nine year long relationship I did not see what was so obvious.  She is my best friend, I know her better than anybody else in the world, but some how I saw all of her behaviors first as something she would go out of,  then as a lack of caring, then as narcissism.  Now I see this amusing cycle. I get up in the morning I take my medication I go to work and by the time I get home the medication is worn off. I wife meanwhile  adds to the chaos at home. I wife works part time and partially from home.  We try to share all of the responsibilities of maintaining our home. I grew more and more resentful that she would not do her part, especially since organization is so hard for me.  Since I was the one who is ADHD her inability to  do her half felt to me like she had no compassion for my difficulties.

I'm very aware of my massive role in this situation. I have behaviors of a ADHD person and an ADHD spouse. What a mess.

 How can I convince her to get tested?  We are trapped in a cycle of me nagging and pushing and her shutting down. I don't even know how to bring this up and get follow through without immediately falling into the same cycle.  What if she's not ADHD,  or there is something else going on that explained  her behavior? Or what if she is ADHD but she tests  negative? I think this is totally possible because she's always blaming other people and circumstances for her disorganized behavior. When asked point-blank if she has trouble completing projects on time it's likely that she will say no.  In couples therapy she was talking about how  her days were incredibly busy saying that she was booked from 6 AM to 6 PM in multiple places.  When the reality is she was working two hours in the morning, from 7 to 9 AM and then had another one hour appointment at 5 PM with the entire day free. She works about 15 hours a week. 

Is there a script for convincing somebody to get tested?  And if she does go and get tested is there anything I can do to get her to accurately describe her behaviors? 

Please help