Geez that reverend is short-sighted. Why not fork over cell-phone address books, e-mail login info, any info for online gaming logins? And while we're at it, let's put tracking devices on our spouses and significant others. Why is it so easy for people to blame Facebook and Craigslist, etc. for their spouse's infidelity? If he/she's determined to cheat, he/she's going to find a way to cheat, no matter how well you watch them. My stepfather ran around on my mom for at least 6 years before he finally left her for some other woman and he didn't even possess the tech savvy to check the voice mails on his cellphone. If the good reverend would spend a little more time counseling and a little less time scapegoating, he might be able to figure out the real reason some of these people are cheating.
Facebook may make it more convenient, but a cheater's going to cheat wherever the opportunity presents itself. In the meantime, some of these trust issues he's encouraging will drive quite a few people apart because they won't have any room to breathe. Sometimes a person just needs a little space outside of their relationship to decompress and relax away from some of the issues that are a part of every marriage, friendship, etc (a little time to watch the game with the fellas, a monthly shopping trip with a few buddies, Saturday afternoon golf/basketball/tennis, whatever your thing is). If spouses start taking that away from each other because they don't trust each other to be out of sight for more than a few minutes or because they need to be a part of everything the other does, I can see divorce court in the future, whether or not the other person is cheating.