(((hugs!))) hey, you are not a fraud okay!
I understand you, sometimes it can feel like a horrible secret. But it's not, its something very personal to you, it's your choice who you open up to, opening up is a big deal sometimes.
You have nothing to feel guilty about.
Also, as supportive you are to them, if they found out most likely shed just want to try and be there for you. They clearly care.
Keep posting on here if it helps, I'm listening, we all are.
Thinking of you, hugs, jess x