Lance Maggiacomo was out of work, bored and lonely when he started hiding his online relationships from his wife.

There was no affair, only chatting through e-mail, yet it felt like cheating just the same.

A few years later, a reformed Maggiacomo has an in-house check on his impulses. He and his wife Lori, like other Christian couples around the country, share one e-mail account as a safeguard against the ever-expanding temptations of the Internet.

“There’s not a Gestapo, KGB quality to it, like I have to check in with mother before I do anything,” said Lance Maggiacomo, a 40-year-old surgical nurse from Beverly, Mass. “It’s what we believe as Christians: We are our brothers’ keepers. It’s about biblical accountability.”

The e-mail addresses — “tim–shawna” and “christyandbrian” — broadcast the couples’ commitment to all correspondents. If one spouse has a Twitter or Facebook account, the other is usually given the password. Often, spouses have separate work accounts where bad behavior could go undetected. However, the goal isn’t policing each other every minute, they say. Instead, they are doing whatever is possible to avoid keeping secrets.

“It’s not a matter of distrust,” said Ronda Hodge, 53, of Amesbury, Mass., an ice-cream maker who shares an e-mail address with her husband Tom, 60, a landscaper. “We really don’t have anything to hide from one another. We were friends first before we even dated so we’ve got that level of openness there.”

It’s impossible to know how widespread the practice has become.

Couples with a joint account said they never heard preaching about it and didn’t read it in an advice book. Some said they initially created their account for bills and other household business then later realized the personal benefits. A 2003 article published by the conservative Christian group Focus on the Family urged husbands and wives to share one e-mail address, but it was one of many suggestions on preventing infidelity.

Still, the phenomenon has become common enough to merit a post on “Stuff Christians Like,” a popular blog in which creator Jonathan Acuff, an evangelical and son of a pastor, good-naturedly mocks Christian culture and himself.

Acuff shares one account with his wife of eight years, Jenny, and estimates that one-third of their married friends also use one e-mail address. He joked on the blog that he and his wife “cleaved our separate e-mail addresses and lit a unity candle on Yahoo! that burns brightly throughout the virtual landscape.”

“It’s so easy to make dumb mistakes online. We don’t have this precedent for how these online friendships work,” said Acuff, 33, whose posts will be released as a book by Zondervan next year. “For me, it’s just a safety measure. I don’t want to be just floating out there.”

James Furrow, a professor of marital and family therapy at Fuller Theological Seminary, an evangelical school in Pasadena, Calif., said sharing an account can be helpful if the goal is promoting openness. But he said the practice can hurt a relationship if it’s meant “as an act of deterrence.”

“We can take steps to manage our behavior, but then the problem with that is it begins to become the emphasis rather than the trust of giving the other the benefit of the doubt,” Furrow said. “What you end up with is the doubt.”