Strangers often trust Edward with their secrets, whether it be on planes or walking down the street. He even became a confidant in one place that he doesn't want most people to know he spent time: prison.

Edward's biggest secret is that he is a convicted felon, having been arrested twice for driving under the influence of alcohol. The second time, he spent 90 days behind bars contemplating his life.

Those reflections helped him make better life choices in the 10 years that have gone by since, he says. But he belongs to a professional organization that would boot him immediately if anyone there ever found out about his conviction, and he still fears that someone in it will discover what he's hiding. Edward, and the others who agreed to speak about their personal experiences for this article, asked that their real names not be used to protect their identities.

"It's not shame that's the reason I'm holding secrets in, especially with the DUI," says Edward, 35, who lives in the Midwest. "It's more about, I don't feel like getting into the story again to have to explain why I'm not your typical felon" -- a violent or sexual offender.

While he says he feels no guilt or shame about his criminal record, he laments he can probably never run for public office because his secret would emerge.

People keep secrets for all kinds of reasons.

Sam von Reiche, psychologist and success coach located in northern New Jersey, believes everyone has secrets to some extent.

"We all end up with some sense internally that we've done something wrong, or that there's something wrong about us and a little deceptive," she said. "I think that's just part of the human condition."

Generally, says von Reiche, "secrets do create a lot of separation from other people, and they also prevent you from feeling truly authentic." But psychologists say there are also situations where it might be better to withhold information from people, even close friends, if the revelation of secrets would cause more pain to you and others.

Abuse

Nancy, 21, is still dealing with her feelings toward her ex-boyfriend, who physically abused her. They were together for four months in college and then broke up -- at least, that's what Nancy's friends thought.

But secretly, Nancy went back to him after one week. She didn't want her friends to know because she knew they would think it was a bad idea.

"I was just convinced that he was going to change, and it was my fault," she said.

But he didn't change. Three months later, Nancy's relationship ended when, she says, she had to call the police because of his abuse.

Nancy, who also lives in the Midwest, has seen a therapist, but secretly longs for her ex despite the abuse. She found a website called Secret Regrets where people can anonymously share situations that no one knows about.

"I regret not being able to let you go," Nancy wrote in a post. "I came back to you for the second time when I knew exactly what was going to happen."

Kevin Hansen, who founded Secret Regrets, has collected about 25,000 confessions from people who are hiding something from a lot of people. The sentiment among many of them, he says, is "nobody else could possibly understand what I'm going through, so I'm not going to tell anyone." Anonymity makes it more comfortable.

Hansen "has always been passionate about helping people," according to the website. He studied psychology and human behavior while earning a business degree, "and now, he's discovered an amazing way to reach people struggling with the biggest regrets of their lives, and connect them with others who know what they're going through."

The feedback from other anonymous users has helped, Nancy said. Some of the messages said things such as "you got out a lot sooner than me."

Anyone who has secrets about abuse should seek professional help, says Bobbie McDonald, a psychologist in Newport Beach, California. Revealing details of an ongoing situation can be risky, as an abuser's behavior can be unpredictable. A counselor, psychologist or expert at a hotline can help put the person in touch with the right resources.

Abortion

Irene, 23, found out she was pregnant in August 2009. Her boyfriend at that time didn't want her to keep the child. Initially she wanted to go forward with the pregnancy, though she later changed her mind.

Irene, who lives in the South, didn't tell anyone in her family about the pregnancy until after the fact. Her mother didn't speak to her for two weeks, but eventually calmed down, she said.

Everyone she has told has been supportive about it, but it's not something she shares with everyone. Her grandparents, for instance, still don't know. Like Nancy, she found support on the Secret Regrets website, where women in their 60s tell her things will get easier with time.

The pregnancy and abortion used to be a source of shame, and Irene used to cry about it a lot. These days, she is able to tell herself that she made the right decision. She was able to finish school and move on from a dysfunctional relationship with her former boyfriend.