Is your wife getting treatment?
It’s important to try to separate your wife from the disorder. And, to remember that ADHD is not a choice. If your wife had a medical condition, say Diabetes or Cancer, that caused all of the same symptoms… would you be thinking of leaving her then?
ADHD in relationships can be hard, but it can also be managed. It may take work on both peoples’ parts, including even the possibility of counseling.
If you’ve been together for 5 years, though, and you’re thinking about leaving, my guess is there are other things that are driving those thoughts. You probably knew who she was and house she was when you first started dating her, and I imagine a part of you even loved that. If she hasn’t changed over that time, maybe you have. Maybe you want different things, or maybe there’s unhappiness somewhere else in the marriage.
Bottom line, be honest with her and with yourself. Marriage deserves honesty and respect. If you want to fix this it can be done. But if you’re looking for a way out, then you need to be honest about that too.