Not just wrong, impossible. They WILL find out eventually, so better if you tell them. My girlfriend used to mind but now that I've forced most of the drug propaganda out of her head, she couldn't care less what I take and when 
being woke up at 3 am by a girl u love holding a baggie of 30 used needles all hysterical cause she searched your apartment while u were sleeping sucks major ass... anyone else been there?
Hmmm - if you can't share your favorite recreational activities with your partner I'd say maybe you are with the wrong partner. I couldn't imagine hiding recreational drug use from my partner. Heck, I couldn't imagine not doing them with my partner. Haha! Don't you think you would enjoy your rolls/trips whathaveyou much more if you didn't have the guilt/paranoia of getting caught nagging at you? Think of how much more fun it would be if you could share those experiences with your partner!
Haha, is it morally right? NO! But everyone does it, and most will eventually get fucked for it
It depends if your wife is a fucking lunatic like mine.
Yeah, thats why people lie. They want to get laid and so they keep people around even though they are not a good match.....if you have to lie then you are not an ideal match, or else your priorties are messed up.
