<human>: Give me a shortened version of the text

Going to make this long story as brief as possible. 

I am a seventeen year old girl who is a senior in high school. I decided to run cross country this year, after three years of track. My longtime friend, Matt (18 and a senior), one of our best distance runners, had taken notice of my hard work... He started displaying clear interest in me and I rejected him. The last time I rejected him was in sixth grade. 

He didn't take this well. For all three and a half months of cross country, he spread rumors about me and would message me awful, awful things. I had to block him EVERYWHERE. What he did actually had a profound impact on me.  

He is the only person I have ever despised and I am a very forgiving person. 

Flash forward, he started hitting on one of my best friends, also seventeen, two months ago. She has a boyfriend and flat out rejected him. 

Consequently, he started hitting on my other seventeen year old friend- she reciprocated. After having a very tearful conversation with her, I recounted everything he had done to me and she said she wouldn't talk to him anymore if that is what I wished. I said I couldn't force her to do that, but if she continued things, it would hurt me. 

Currently, they are dating. She told me she has nothing to apologize for. 

Matt is committed to the marines, and therefore, is leaving the week after high school ends. 

I am still kind of dumbfounded. We are all seniors, and therefore, we are all bound to part ways. I was just hoping I could have a few friendships endure... I'm just not sure if the friendship I maintained with her should be one of them.
<bot>: She is choosing a relationship with an expiration date of two months over a best friend of three years. Should I forgive her?