<human>: Can you provide a brief rundown of the text in within 3 sentences?

I (M 21) have been in an amazing relationship for almost two years with my beautiful girlfriend (F 20) who I love very much. We've been extremely happy besides a few minor things that everyone has. This is one of them. 

Early in our relationship, we had talked about past relationships and specifically this one that kind of worries me. There's this guy she pretty much grew up with and had lived down the street from her whole life. She has admitted to having strong feelings for him before, and even left a previous relationship specifically for this guy.

Through my relationship with her, he hasn't had much presence until recently. I noticed she would talk about him more and more, and now they're even going to the same college together and living in their own apartments across the street from each other. I have continuously expressed my feelings to her about how I'm a little wary about it, but she doesn't seem to give a shit. Last night, she said she was going to visit him around midnight and was there for about half an hour. 

I know I'm being paranoid and I feel so guilty about it. She thinks that I want her to stop being friends with him, but I don't want that at all. I want her to have friends, especially life-long friends. I dont want her to give that up because of me. Im just nervous because of her past feelings for him. 

Am i overreacting about this? Im kind of weirded out about last night. Do you think there is nothing to worry about? How can i become comfortable with this? What can both of us do to make me less nervous and more okay with it?
<bot>: nervous about girlfriend hanging out with a guy she has expressed feelings for in the past (now says those feelings are gone) but I want to be more comfortable with it