I have tried on many occasions to explain to SWMBO the ins and outs of building a traction engine (or two
) and the tooling requirements, expenditure etc surrounding those activities.
She now does not even venture into the workshop and if I am required on the phone, I get a shout from the workshop door – 'I'm not coming in but so-and-so wants to talk to you'
What a great life being a model engineer 
If I buy something, I now get the reaction – very nice dear, but rarely get asked 'how much was it?' or 'what does it do'
But then I do acknowledge her indulgence in jewellery, and trust me, I could have equipped a very nice workshop over the years – but would have been a very lonely man
such is the acceptance of married life.
I don't care if she doesn't know 'what it does' I don't see any more use for a diamond than for truing up my grinding wheels – but then who am I to question LOL
CB