How much do you know about your spouse? Hair colour, date of birth, where they grew up, what they do for a living…how much they earn, perhaps?
Not so much that last one, according to a number of respondents to a popular thread on Mumsnet last week. The proportion of respondents who do not know how much their husbands and partners earn was surprisingly high.
'I have a rough idea,' said one. 'We keep our finances separate. As long as he pays his share of the bills, it doesn’t matter,' said another.
Prudential, the insurer, found that 12 per cent of Brits do not tell their partners what they earn. Such is the British paranoia surrounding financial disclosure that some couples are willing to share a bed, a house and sexual preferences with another human being, but not the amount they bring home each month.
What are they so afraid of? Being judged for not making enough? For earning too much? Your partner only loving you for money? Your partner not loving you because you don’t earn as much as they thought?
Couples who practice financial secrecy need to do themselves a favour and get their spreadsheets on the table.
For one thing, keeping earnings a secret is extremely impractical. How do couples who don’t share such information get through planning a wedding, making a mortgage application, having children? Did 'DH' (that’s Dear Husband in Mumsnet-speak) ask his Mrs to leave the room when the mortgage broker asked for exact income?
One contributor to the Mumsnet thread pointed out that if your spouse earns an awful lot, then it's probably less important for you to know the precise amount than if he or she is on a lower income and household budgeting is a real concern.
But this also suggests that one partner holds all the financial cards and the other is effectively dependent, happy to remain blissfully ignorant as long as they are kept in clover.
Leaving aside the power imbalances and clear control issues evident in a relationship where one person or both keeps their finances secret, are those that keep schtum also worse with money as a result of their refusal to talk about it?
Joe Deville, a research associate at Goldsmiths, University of London, thinks that openness and transparency about finances, not just with spouses but with others generally, can be a way to avoid or find a way out of debt. Sharing financial information is a sign of a healthy attitude towards money.
Not knowing your own financial circumstances is also stressful. The top money management tip to avoid such stress from Mind, the mental health charity, is: 'know how much money you have'.
And if you live with someone, have kids together, a house, holidays and share meal-times, that means how much your other half has too.
Rebecca O’Connor is the founder of Good With Money and a former financial writer at The Times