In the world of personal finance, the subject of how couples share (or don't share) their money comes up time and time again. It's no surprise. After all, money problems are a leading cause of divorce.

But for some reason, the concept that "personal finance is personal" doesn't always factor into people's opinions about combining finances -- especially within a marriage.

Often, people argue that in order to be a team, couples must combine finances fully. Or that separate accounts mean there's some lack of trust within the relationship. Or that you aren't truly committed to each other. Or that you must not be on the same page about long-term hopes and dreams.