"It's very normal in a couple that one person is a spender and one is a saver," Sussman said. The problem is "you think you're justified and the other person is at fault." The saver might accuse the spender of being fiscally irresponsible; the spender might accuse the saver of being cheap.
Don Cloud, president and founder of Cloud Financial Inc., previously told Business Insider that he frequently works with spender/saver couples. The first step, he said, is for each partner to share their beliefs and feelings about money.
Yet Sussman said issues also tend to arise when couples move in together or get married and face the decision about whether to combine finances, a notoriously difficult choice. If they're hesitant, "might this show that there's a lack of trust?"
Or, fights about money might come up later in a relationship. Maybe both partners worked when they started dating, but once they had kids, one partner stayed home. The partner who works might be "holding that over [the other partner's] head," or even engage in financial blackmail, Sussman said.