Once, I dated a man, who was very, very poor. That’s what he said, and I believed him. Why wouldn’t I? He had wads of medical bills left over from a bout with cancer; he had child support; he had business expenses; and—oh, yes—he had the Chinese symbol for money tattooed on his Achilles tendon.

Since I lived in Manhattan and he was in North Carolina, we spent much of our relationship commuting. Plane tickets cost money, and though we tried to split the fares, I ended up paying for the bulk of them.

I didn’t really mind. He’d had a hard couple of years; I’d just sold a book and had some extra cash, and I wanted to see him. I was hardly wealthy, but if I had to shell out more money than he did, so be it. He wasn’t so happy about the financial disparity.

Though he would never admit it, much of his masculinity was tied up in his wallet; he felt less virile for not being able to pay his (and my) way. And I’ll confess: sometimes, it bothered me too. Such as the time I eyed a $70 dollar bracelet in a store window hoping he would buy it for me (he didn’t), and when I wondered how we would afford to have kids if we ever reached that point (we didn’t).

But for the most part, our money issues weren’t a problem for me. That is, until he canceled a trip we’d planned to Panama— after I paid for the tickets, mind you—pleading poverty. A few weeks later, he mysteriously found the resources to buy a brand new motorcycle.

I was livid; I was hurt. I couldn’t believe he’d canceled our plans, especially when he knew how important they were to me. And for a motorcycle! “I thought you didn’t have any money!” I said. “I put it on my credit card,” he replied. “I can always sell it. You can sell an object. You can’t sell a trip.”

And that’s when I realized that our issues weren’t about money. They were about priorities and power and his need to assert himself in a situation where he felt inferior. The one way he could do it? By hitting me where he knew I’d feel it.

It goes without saying that relationships are tough work, filled with endless compromises—and many couples feel the challenges smack in their billfolds.

According to a 2006 Money magazine poll, 84 percent of respondents reported that finances caused tension in their marriages, and 15 percent said they fought about money several times a month. Sharyn Sooho, a Boston divorce attorney and cofounder of divorcenet.com, notes that one spouse earning significantly more than the other—or experiencing overwhelming success—is a leading cause of divorce.