Hey Zig, don't take this wrong but your posts made me smile. Only because I've been there and done the same thing.
I remember one time my W had asked for my help on something so as I was trying to understand some things, I asked questions. She had no patience for the questions (looking back she must have thought I was questioning "her" and not what was going on) She started snapping at me and critizing. So I stood up and said 'do you really want my help or just an opportunity to insult me?" It got her attention. Not my best moment but it also didn't make the difference in our M. Life moves on.
Hope your S is OK.
Me:45, W:45 S:16 D:13 M:22, T:25 Bomb: July 2010 Putting finances in order for "D" Continue to live in same home-separate rooms