<human>: Provide a brief overview of the text.

Recently, my girlfriend and I have been having some troubles.  I had gone away on vacation and a guy that she had hooked up with when we were temporarily broken up had messaged me on a social networking site and told me that she had cheated on me with him.  I had asked her about it and, because I trust her, I believed her word when she said that there was nothing going on.  Ever since then, things have started to get kind of weird.  Any time I glance at her phone, she quickly pulls it away and anytime I see that she gets a text, she immediately closes it and acts like there was never anything there.  On top of that, she has recently been accusing me of cheating, which I have never done and would never do.  Something in my gut is telling me that this is some kind of guilty accusation and I'm really hoping nothing is wrong.  I apologize for the wall of text, but the great people of reddit have helped me in the past and I was just hoping that maybe some more good advice was out there.  Thanks if you read all of this, and I would really appreciate any feedback.
<bot>: Girlfriend is acting very odd and I have a hunch cheating may be occurring and I don't know if I should approach her.