Beware the Affair Scam (Especially If You're Actually Having One)

Look, we're not saying that you cheated on your spouse. We're not even saying that you've thought about it, received a steamy email, or had a stranger's number burn a hole in your smartphone. All we're saying is that some unsavory scam artists are playing the odds that your marital history is less than pristine, and hoping your insecurity will lead you to paying some big bucks to keep them quiet.

The first step to avoiding the scam is obvious: don't cheat. After that, know that the scammers probably don't have any real evidence, and report the incident.

Broad Bitcoin Blackmailing Scheme

"I know you cheated on your wife." That's how the letter Dave Eargle found in his mailbox began. "It is just your bad luck that I stumbled across your misadventures while working a job." The letter assured Eargle that the writer was "ready to forget all about you and let you get on with your life." All he had to do was fork over $2,000 in bitcoin.

Eargle had never cheated on his wife, but the letter gave him pause. "And I had to think for a second because I was in a bit of a fluster," he told CNBC. "'Am I actually keeping a secret from my wife?'" Eargle wasn't, so he contacted police and blogged about the letter. It turns out he was far from the only attempted victim. Based on responses to his blog, Eargle determined the letters were sent out in waves from various locations nationwide, but the message to pay up or be exposed as a cheater was always the same. "It was really comforting to find out that I wasn't probably being necessarily targeted," he said, "that this was just part of some more broad blackmailing scheme."

Getting Lucky

That might be little comfort to spouses who are stepping out on the side, and the scam probably worked to some degree. "The amount of money is such that it's not so much that someone might be willing to just pay that to make it go away," Patrick Wyman, a supervisory special agent with the FBI's money laundering unit told CNBC. "They're hoping that they might get lucky with someone who actually ... [has] some infidelity there. And if they hit that target, that's a person who's probably willing to pay."

Eargle also noted that later versions of the letter increased the bitcoin demand to $8,000, meaning that some of the scam's targets probably paid up. But that doesn't mean you have to -- because of course you didn't cheat, right?