I used to taker psychedelics in secret around my ex-girlfriend/wife for years. I did it because she early on shut down my attempts to be honest with her about it, and ridiculed me for wanting to trip, and prohibited me from doing so. I felt (rightly so) that it was not her right to dictate that to me. So for many years I hid it from her. Eventually it came to a head and was very painful for us both. It was part of the reason we split up, but not all (she was controlling and abusive). I don't regret doing the tripping as it was important to me, but what I do regret is not seeing the warning signs early on and ending the relationship before it progressed. If someone does not accept you tripping (assuming you're not being self-destructive about it of course), it's highly likely they're not the right person for you. Lying about it to your significant other is morally wrong, IMO. You have a greater obligation to being open and honest to a significant other than you do to anyone else, because you've agreed to share your life with them and be at that level of intimacy. If you find yourself lying to a SO about drug use, in my (experienced) opinion, it's a red flag that something is seriously wrong.
Lying to friends or family about it is a little different, more situationally dependent. If you're living under your parents' roof, and you have to hide it, then it probably means you should wait until you are living on your own. If you're an adult and you trip and your parents would be freaked out by that and it comes up and you lie, that's appropriate, I think. At that point, it's your business and by not revealing it to them you're just saving you and them pain.
