<human>: We have been together for a year now, she's fun to be with and I have never doubted she's cheating on me until I saw something.

My friend came to town a few days ago and I drove him from the airport to a hotel close to my place. He insisted that we have coffee together and talk a little and so I did. Then I saw my girlfriend in one of those glass elevators with that guy from her class. They were holding hands and she had her face leaned towards him.

I didn't follow them. I didn't say anything to her. I know the excuses she'll come up with. But suddenly everything started to make sense. I know why they always acted weird around me. I decided to let my anger settle for a while before I confront her and now I'm wondering if I should confront her at all.

I'm really sad about this. It's not like I'm forcing her to stay with me. She can go out with that guy if she wants but she has to breakup with me first. I don't know what to do. I have never been in such situation before. Please people help me if you've been there before. 

Also, she suffers from anxiety. I'm afraid I'm going to make it a lot worse if I confronted her.

Can you condense the text into a few key points?
<bot>: my girlfriend of 1 year cheated on me with her classmate. I don't know how to handle the situation. I need some advice