Amy and At-Wits-End -
I've been where you are. It can be incredibly frustrating and sometimes alienating. Here are a few things that have helped me cope.
1. Therapy on my own for anger issues which was really an anxiety problem manifesting itself as anger.
2. Letting my husband's smaller daily struggles be his own. This is very very difficult because of our natural desire to step in and help. If our help is unasked-for, it only makes your partner feel like a child and doesn't help him/her on the skills that they need to work on. If he askes me to help find his keys, remind him of something, schedule something, etc, I'll gladly pitch in. I'm more proactive in the bigger things that affect us as a couple and have found that this relieves me of the daily kvetching.
3. Don't expect the ADD to be totally fixed with drugs and therapy. These help but the underlying condition is there. Setting your expectations on a total cure will only lead to dissapointment and frustration for both of you.
Besides doesn't "fixing" imply that your partner is essentially "broken." How do you think that makes them feel? If your partner had, say, diabetes, would you expect them to be cured? No - you'd expect that they be treated.
I hope some of this helps. Despite these strategies, I still get angry and frustrated sometimes but that's true for any relationship. Try to remember and celebrate the things that attracted you to your partner in the first place.