“We thought it would be the incongruent or unmatched pattern that would be most problematic, where one’s a spender and one’s a saver,” Carroll told LiveScience. “Our study found that it’s the couples where both spouses have high levels of materialism that struggle the most.*…

It seems reasonable to expect that mismatched marriages would be the unhappiest, given that a marriage between a spendthrift and a saver would seem headed for conflict. But that’s not what the study found, Carroll said.

“Even when it’s a shared value, [materialism] seems to have an additive effect,” he said. “It seems to compound the problem.”