I personally have enough on my plate that I need people in my life who I can trust, and none that I can't. I don't have the time or energy to waste checking up on people. There is not a soul on earth who is worth me having to do that much checking up on.
I do agree whole-heartedly, L2L. However -- the "complete honesty" is something friends of mine have used successfully when their partner has cheated and they're committed to doing what they can to save the relationship. One of my friends said she never did "check" on her DH after the first month, but just
knowing that there were no secrets between them helped her rebuild trust again.
Of course, it's up to each person/couple how you handle things like that. I know exactly how easy it is to get a second (or third, or fourth) web-based e-mail account or a pay-as-you-go phone if you
really want to continue cheating, so that stuff wouldn't work for me either.