I think our parents don't know that the wedding was fake
Why would they think it's a fake?
They will find out sooner or later because I'm going to tell them.
You should tell them because trust is very important and that is why they didn't realize the wedding was fake. If you break the trust, then everything you do in the future will be doubted so you shouldn't keep secrets from your parents.
Are you trying to tell me about secrets? What secrets do you have?
My secrets are not relevant. What you are doing is wrong and you need to tell your parents.