What’s more likely to end a relationship or a marriage—money trouble or infidelity? According to multiple studies, the answer is the former.

Researchers and survey studies in Australia and the U.K. have identified financial stress as the primary reason driving couples apart. In the U.S. at least one study has ranked money as one of the top reasons marriages and most relationships end.

It turns out that the one thing that strains relationships the most is the thing couples loathe to talk about.

Financial stress is not related to just one problem. In fact, “money problems” in a marriage could relate to a variety of finance-related issues.

Here is a list of pervasive money problems in marriage that could most likely break an otherwise solid relationship:

Too Much Debt

Debt typically comes out on top as a reason for couples to divorce. Marriage-ending debt is usually acquired following the marriage. One of the first things newlyweds undertake together is taking on more debt. People who are already saddled with student loan debt may take on even more debt as the form of mortgages, vehicle loans, or personal loans.

Debt can cause stress regardless of whether a person is in a relationship or not. Some may assume that accumulating debt as a couple is better than doing so as a single person. Couples have combined incomes and the ability to talk things through and plan, right?

In reality, household debt only leads to arguments between spouses, with money being the most contentious issue. The arguments may then spiral from financial concerns on to other topics. Debt doesn’t only ruin credit ratings, it ruins intimate relationships too.

Gambling

Gambling is an age-old reason for marriages that end in disaster. Spouses in modern times underestimate the toll gambling could have on a marriage. It’s enough for only one partner to be a gambler to end a marriage. If both partners are gamblers, the couple may end up not just divorced, but in legal trouble as well.

When we hear the word “gambling” today, we think of sleazy casinos and crime bosses. While that sort of gambling is still prevalent, there are other, more thinly veiled, forms of gambling that should be a source of concern for families. For example, so-called investments that rely heavily on speculation are really just forms of gambling. So a partner that “invests” and ultimately loses money would bring home only trouble.

Income Differences

Sometimes making money is the cause of financial trouble at home, not losing money. When a couple has a significant difference in the amount of income either partner makes, trouble crops up in the household.

For some, having a partner that makes a lot more money may come as a relief. However, the richer spouse or partner may then try to solely control the household budget, not taking the other partner’s financial concerns into account. This would naturally lead to arguments and eventual divorce.

Spending and Saving Imbalance

Partnerships come to a swift end when one half of the couple likes to spend and the other prefers to save. It’s easy to believe that the saver would cancel out the deficits of the spender, and vice versa. Not so in real life. Couples typically get into arguments over constant spending or being unnecessary frugal.

Unrestrained spending habits can lead to financial trouble, of course. In a relationship, that could also cause a significant source of stress for the partner that wants to be thrifty. More often than not, the stress comes to a breaking point and the relationship falls apart.

Debt, income disparities between partners and personal values about spending money are the main issues that drive couples apart. Ultimately, couples that don’t want to address money issues head-on, won’t last long together. Both financial advisors and relationship counselors recommend couples to seek professional help if money has become a major source of stress in a relationship. As with most things, discussing and planning together can help a couple overcome these pitfalls.