Of course, most of us do not have to worry about marrying a diabolical killer, but Marquet says there are still instances that cry out for some investigation.
"They're saying things that are inconsistent, or they're telling stories, or they're disappearing for periods of time and you don't know what they're up to, you might want to dig a little deeper," he said.
If you are one of the millions of Americans who use an online dating service, do not rely on the sites to vet your potential partner. The major services all carry disclaimers.
"It's up to you to research and do your due diligence," says Match.com, in an entire section of the site devoted to safety.
Dating service eHarmony cautions that while it does monitor for unusual account activity, "eHarmony does not conduct criminal background checks at the time an account is registered."
Of course, running a background check on your partner can throw a wrench into your relationship should your partner find out. But Marquet says it may be worth the risk.
"Wow, you did that on me? You know, I can't believe you don't trust me. I can't believe that you would do such a thing. Yeah, that's a tough thing to overcome," he said. "But sometimes, the truth is the truth. If there is a problem, or there are issues, and they're not being forthcoming, and you literally have to go that far, it's defensible."
Besides, there nothing that says you have to check out your partner behind his or her back. Still, if you feel the need to run a background check on your significant other, should you be with that person in the first place? Marquet says that is a false choice.
"Oftentimes when you're going out and you're on the dating scene or whatever, your tummy will tell you pretty quickly. Yes, no. Boom. You move on. But sometimes it's not so clear," he says. "I'm not just protecting myself and my feelings, I've got family, I've got an estate, whatever."
We will never know if a simple background check would have saved Linda Curry's life. After all, it would take another 16 years for authorities to finally crack the case. But trading a little romance for a little bit of research might have at least given her a fighting chance.
Go inside Paul Curry's toxic plot, and see how authorities finally solved the crime, on an all new episode of "American Greed," Monday, June 19, at 10 p.m. ET/PT on CNBC