Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: I’ll start by saying I’m a dude. I’ve been best friends with this girl since early high school. Been through thick and thin together for years and she was like a sister to me. We went to separate universities but still remained very close and saw each other all the time. Really one of the best friends I’ve ever had. 
I introduced her to one of my best friends in college. Long story short, he was not a good friend because he was very condescending toward me, blamed me for things that weren’t my fault, and he distanced himself from me when my dad passed away because he didn’t want to deal with it. 
I recently found out my “best friend” from high school is now dating my friend from college who treated me very poorly. I openly told her how much I disliked him, and she would agree. And now they’re dating. I completely stopped all communication with her as soon as i found out (I found out through a third party) and so far i don’t regret it. But am I overreacting? Is this something to even hold a grudge over? I have no desire to talk to either of them but sometimes I feel like I overreacted to the situation and i should’ve just talked it out instead of cutting her off. But I feel kind of stabbed in the back from this whole situation also. Just not sure what to do. 

cutting off my best friend