8. The location of your porn stash
Guys like porn. A lot of chicks do, too. There's no sense, however, in mixing up your fantasy world with the real one. As soon as your lady gets wind that you have a porn stash, there's a good chance that she'll be crying about how she has to compete with Jenna Jameson whenever she sleeps with you. And man, you do not need that kind of stress every time you want to get it on. Worse still, she could get all crazy and throw out your collection when you aren't looking. Protect your porn, and keep it under wraps.
7. Your weaknesses
Maybe you cry during insurance commercials, or maybe you aren't really as self-confident as you make yourself out to be in public. These frailties don't matter — as long as she never finds out about them. If she does, she'll start making all sorts of "cute" jokes at your expense. Or the revelation that her man isn't quite the man that she thought he was will put her off of you entirely. Be strong and keep your weaknesses undercover.