According to ABC, it's become trendy for Christian couples to share their email and Facebook passwords with each other. Of course, every couple insists that it has nothing to do with not trusting their partners, it's about not trusting themselves.
Um, what's the difference? If anything, not trusting yourself is worse. You have no control over what your spouse does. If she is going to meet up with her old flame at the Motel 6 you really can't stop her. You can control your own actions though. If you need to have your spouse looking over your virtual shoulder 24 X 7 to stay faithful your relationship has bigger issues to deal with.
Other couples in the article say they want to share everything in their lives. I'm guessing most of these people are newlyweds. I can't think of a quicker route to divorce than forcing Michelle to wade through the various sports, political, or technical discussions I get into over email :)
I'm also willing to bet that somewhere between 1/3 and 1/2 of the people sharing email accounts have a secret Hotmail / Gmail account that their spouses don't know about. I'm just cynical that way.
I'm not saying a shared email account is bad. I'm saying the idea that a private email account will lead to infidelity is stupid. If you can't carry on a conversation with your prom date from 20 years ago without becoming overwhelmed with thoughts of infidelity, sharing the email account is only treating the symptom.