For the 'marriage experts' in here who think his marriage is fragile, etc - God, stop over-analyzing everything.
It's not about him being scared of his wife, it's that women tend to remember all the expensive purchases we make, so they can remind us later to buy things for them in the same price category - for e.g.
Me: Nah, those earrings are too much babe, you really don't need them.
She: Oh yeah? Then why did you buy a 4k mac pro?? You could have bought a 699 hp huh? Is it because when YOU want to buy stuff it has to be top-notch? (continue saga..)
They have an uncanny memory for all those types of things - my friend's wife still keeps reminding him of the plasma tv he purchased 2 years ago (he had always wanted one) It's not worth all the little arguments - so when I do buy something expensive I always tell the wife I got it for 50% off
And seriously - what the hell is up with these forums? Everyone always makes stupid, unnecessary comments on how a person should live his/her life, or why they need to buy this, etc.. instead of answering the bloody question!