I'll never tell whether or not I'm seeing people from these sites when my girlfriend is out of town or if I'm texting/e-mailing with other women. I keep my phone, computer and iPad all locked up, she'll never figure out the passwords so I'm not worried about that. As long as she believes I'm not that's all that matters.
If I don't start telling her truth instead of making my girlfriend feel crazy when she finds other women's things when she gets home then I"m going to be single very soon. Also, another secret I"m keeping from her, I'm not ever going to ask her to marry me even though I've been leading her on to think I want to. hahaha! I've got the best of all worlds and the greatest thing about that is none of them will ever know each other.