Don't give me dialogue of a character saying "I'm doing this for your good".
I want to know the secret too, I want to be in on the joke. At least give me a hint or some foreshadowing, something! This does not make me like your story more.
We are set up to root for the two leads we will always be on their side don't make it hard for me to like them.
Rule? Yes, the idea of the secret is nice but it can be about keeping it from getting out and the fallout once it gets out. Take notes from gossip girl I guess or what ever scripted drama you like.