<human>: Give me the gist of the text in a nutshell

It's not immediately concerning, though the transparency she's had with some other people isn't the same way she is towards me.

What happened was I opened my computer and her facebook was up. I know it's so wrong and such violation in so many ways to dig around private matters, but not expecting to find anything I looked at her messages (and am still kicking myself for it).

There was a guy she took a course over the summer with, and after some everyday acquaintance they developed a classroom friendship, and it was pretty obvious he was into her.
I wasn't too alarmed, or concerned for that matter, and she handled it really well by politely making it known she was in a relationship, avoiding one-on-one situations outside of class, etc.

But after [wrongfully] seeing their facebook message, I've learned that they've become quite chummy, and when he expressed his infatuation with her (which she told me about) I learned that she, though again handling it well and not pursuing anything, developed feelings for him along the way.

I'm not sure how to go about talking about it with her
<bot>: I saw my girlfriend's facebook messages (I know...) and found out she's had feelings for another guy since we've been together.