I'm sorry, Poshgirl. Dh tends to go back to the same things over and over again, but sadly, he does seem to lose his train of thought easily. It's hard to think of that as a benefit...
Maybe eventually you find some tactics that work with her. With dh, it's kind of an evolution to find new things that work and keep me sane enough.
It's great that you have your hobby. It sounds interesting. Actually, my first thought about her not understanding was that it's because it's not about her. That's how dh is though. Difficult people are, well... difficult.
Good luck next time you have to deal with her.