One theme you see batted around discussions of couples finance is the question of joint vs individual accounts. That is, should a couple have bank accounts that both can access or should they do their finances more separately?
Joint accounts have some virtues. The ones I like are:
1) Flexibility: For example, you can both access the account in a pinch. Also, very often one partner in a marriage may be more interested or have more responsibility for managing the couples money, but the other may want to have periodic access to pay bills or get cash out. Doing accounts jointly can meet the needs of both people.
2) Transparency: One reason why joint accounts make sense is because its harder for couples to hide income or expenses from each other. Sometimes conflict in a marriage gets worked out via money – e.g one partner resents the other and hordes money or overspends in retaliation for perceived wrongs. If you have joint accounts, its easier for both people to see whats going on and it helps to prevent financially acting out.