I do exactly as I'm told in my house - unless I don't want to
.
For those unenlightened souls who feel they need approval for a new bike from the wife/girlfriend/civil partner/husband etc, I shall repeat my tried and trusted advice. Do not buy a bike off the shelf; build it yourself. Take your time. Buy the parts from a number of different outlets over about six to eight months. Get them delivered to your work address or buy from old-fashioned shops as much as possible - most parts are small enough to sneak past prying eyes. If you have to get stuff sent to the house, The Enemy should overlook the odd parcel delivery, and tyres, tubes, chains and cables are just 'spares' anyway.
Get the frame last, as it's hardest to hide, disguise or dismiss as something which "needs replacing every six months". When challenged, explain that your 'new' bike is not really an extravagance, because you're just going to build it up from all those bits you happen to have lying around in the shed [yes, those bits that you've been surreptitiously buying for months
].
If this fails - and I can't think why it would - remember that the answer to all questions about price is 'about £500'. To the non-cyclist this seems like the sort of money a fairly serious rider would spend, but without sounding over-the-top.
[I am not authorised to give financial advice. Consult your IFA if in doubt.]