if your non-ADHD spouse doesn's believe or understand your ADHD?

I have never been formally diagnosed with ADHD, but based on my life history and my neuro-psych testing results "ADHD - highly probable", i believe that i have ADHD (inattentive).  My wife says that i don't try hard enough, that i'm not pulling my weight in the marriage.  She doesn't want to pay to have me tested so someone can us that i have ADHD, because i won't follow thru on anything a therapist suggests (go figure!).  She doesn't really understand ADHD and doesn't want to learn about it.  She says that i am just using it as a "get out of jail free" card when i neglect to do something.  What have others done to get their spouse to understand?