"I was once dating a guy and a year later I found out he was married," one woman said.
Some women say they've heard it all.
"Three days before Valentine's Day, he just stopped talking to me, stopped calling me, stopped texting me and then about two days after Valentine's Day, I spoke with him and he was like, 'Oh my phone, the service just went out. I wasn't getting any calls," another woman said.
When it comes to catching liars, one man says he's seen it all. That's because Rod Demery is a homicide detective.
"The most interesting thing or most exciting part of the work is interviewing and interrogation. That's when you actually study someone to find out if they are being deceptive or honest. And everyone lies," he said.
It's a career influenced by the murder of his mother when he was a child.
"I think the reason that I chose that profession is because I wanted to work crimes and solve crimes -- the fears I had as a child, I wanted to remove those from other people," Demery said.
Demery is also a twice-divorced father of nine. He's combined 22 years of police work with a lifetime of serial dating. He says that's why he wrote the book, "Things my Daughters Need to Know."
"Dads are men and they know exactly how they think. They know how most of their friends or their connections think. Women know what men tell them," he said.
Demery says when it comes to spotting a liar, there are some signs. For example, on holidays and special dates, is he noticeably absent?
"The big ones you know Christmas, Thanksgiving, Valentine's Day. If you are dating someone that is not available on those dates, that is something you should seriously look at," Demery said.
Does he have a paranoid protection of his electronic devices?
"Most people are not that protective of those types of devices unless they're trying to hide something from you," Demery said.
Is there a lack of public display of affection except when you're out of town?
"If they are willing to do it in Dallas but not in Houston, then that may be a problem," he said.
And what about his personal life? Is he reluctant to let you in?
"The fact is that if someone doesn't want you around their home, their family, their friends -- something that they don't want other people to see," he said.
And finally, when you ask a sensitive question, does he always start with 'uh?" or "what"?
"These things are delayers and it's a definite sign of deception," Demery said.
So whether it's solving a murder, or helping women with insider information, Demery says it's about trusting one person -- yourself. When your instincts say someone might be lying, they probably are.
"I would do something different this time. This time, I would investigate a person more, try to go to their home quicker because I don't want to be lied to again," one woman said.