When people ask me: "Can you keep a secret?", I always reply: "If you think it is a secret, then don't tell me". It is not that I can't keep a secret, but I just don't want to be burdened with having to keep my mouth shut because I know something I might think other people need to know too.
I believe secrecy is ruining relationships, whether they are romantic or otherwise. Transparency on the other hand makes for better trust.