because when I tell people about trading currency online our relationship sometimes changes. They start scheming or they think "I can do that, better than you" and I suspect they want to secretly start trading too.
That honestly sounds like a touch of paranoia on your part--but on the other hand, I don't know what people you're talking about. If I told friends/family/coworkers that I'm into crypto (and I have), the last thing on my mind would be that they'd jump in and compete with me. In fact, I'm usually met with complete indifference when I mention bitcoin to people.
As far as being secretive, I'm not. I think I should be more discreet about my dealings, though, simply because there are so many scammers around and I just never know who to trust. That's on the internet, though. In real life, I don't care who I tell. Nobody I know owns any crypto and quite a few of the people I've mentioned it to have barely even heard of it.