on the one hand a male should be able to have female friends but in the context of what you describe I will agree that there is a problem here. First thing to point out is if he is as forthcoming as he implies by some of the things he says and as faithful as he claims to be why would he first hide his texts, then tell you not to use his phone? That along gives enough reason to be suspicious.

I agree with the others to trust your gut, that this is a recipe for disaster. Someone stated that it is an emotional affair and at best even if it isn't now, it seems to be heading that way quickly as personal as the texts seem to be.