All married couples disagree and argue about things. However, according to a 2013 Kansas State University study, money is by far the topic that couples argue about most and, in some cases, arguments about finances can ultimately ruin a marriage.
For many people, money is a taboo topic. Most people prefer to keep details related to how much money they make or how much they pay for certain items private. While it's perfectly acceptable not to broadcast one's financial details to relatives or neighbors, it's another thing when spouses don't openly communicate with each other about finances.