Large, secret purchases. Hidden bank accounts. These examples of financial infidelity are far more common in relationships than you might think, according to a national U.S. poll conducted by creditcards.com. The survey estimates that one in five Americans are making purchases of $500 or more without their partner’s knowledge—with about 6% going so far as to maintain secret accounts. Break down these findings by gender and—surprise!—it seems men are the most willing to deceive.