In Marriage, the Unseen Bottom Line LONDON - When Rachel revealed that her husband was happy for her to buy shoes with their joint credit card, two questions popped into my head: How can I get our husbands to hang out more? And how many pairs of Jimmy Choo and Christian Louboutin could I afford if I was reimbursed for half of all the (much less fancy) footwear I've bought with my own money since I met my husband 15 years ago? More serious is the equally pressing third question: How do modern couples manage their finances - and how does that affect the status of women, their long-term financial security and even their career prospects? A completely unscientific snap poll of 44 girlfriends in Europe and the United States - all highly educated, in their 30s and in relationships, most with children and a job - showed that 41 pooled at least some money with their partners. Dissecting what constitutes joint spending makes for an intriguing study in gender equality: Milk and diapers rarely cause disputes. But what about postnatal yoga? Or haircuts, invariably more expensive for women than men? One friend charges a weekly massage to the joint account, arguing that pregnancy is doing her back in. Another makes her husband pay half her cellphone bill; his is covered by his employer. A third shares all her waxing expenses in the spirit of he-can't-share-the-pain-but-he-can-share-the-bill. I asked Paul, Rachel's husband, why he felt that shoes (and, it turns out, makeup and clothes! What am I doing wrong?) should be paid for by the joint account. "There are so many explicit and implicit requirements on how a woman should look," he said. You shouldn't be punished financially for being female, he said. Caitlin Moran, author of the best-selling "How to Be a Woman," called it a tax on being a woman. For a woman to feel normal she has to spend more than a man. If you don't want to have to justify yourself every time you walk out of your door, you have to throw some money at it. Some people don't care about societal norms. That doesn't change the tricky trade-off between equality and independence that lies at the heart of family finance. When women have children and one parent, still usually the mother, sacrifices at least some earnings to maternity leave or part-time work or a less ambitious career, the notion of equality would seem to demand that both parents pool their (often different) incomes and decide on an identical spending allowance. But in my mini-survey, 30 of the 41 women with joint accounts preferred keeping their (often lower) salaries in a personal account and paying a pro-rated amount into the family pool in order to enjoy some unscrutinized spending. "I know that a lot of my spending is frivolous, and I couldn't defend it if you shoved a spreadsheet in my face," said one American friend who has been resisting her fiancé"s efforts to open a joint account. But "the thought of having another person in control of - and able to make comments about - my spending habits makes me antsy." Indeed, several friends have found creative ways to maintain the independence they ostensibly sacrificed in the name of equality. One has a secret trove of prewedding savings she never mentioned to her husband so she can spend beyond the jointly agreed monthly spending allowance. "I like having a bit of a buffer," she says. Another tries to get away with the occasional shopping spree by buying her husband a new pair of shoes for every pair she buys herself. But if the women spend the money, the guys control it. Only one of the friends I interviewed is in charge of family finances (her husband once forgot to cancel his gym membership when he changed cities because he didn't check his bank statements for 18 months).