I think my boyfriend of two years is a peeping tom and has been cheating the entire relationship
Who do you think he is peeping on?
He keeps checking what I do on FB and my messages.
I'm not sure if that's being a peeping tom. It's more like he wants to know everything about you, which is a little overbearing.
I'm sure that he's been looking at all of this.
It may be better to simply ask him about this. If you simply think he is doing it but have never talked about it with him than you are only causing yourself worry.