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: So the backstory.
3 years ago me and this girl were in a relationship. It was highschool senior year (I'm not from the US so we don't have a relaxed dating culture) the first time for both of us and lasted for 4 months before she dropped of the face of the earth for a couple of days, and ended it without giving a reason. We never fought or anything, and she constantly avoided telling me her reasons so I was left wondering why. I had a 3 year crush on her as well so her leaving me fucked me up for a good year or so before I got over it. Also vital information, both of us share a very close friend and practically the same social circle.

Fast forward 3 years. Me, my ex, and our friend all end up in the same college and same major. Since then I've dealt with my ex a number of times and we never really had a problem. All 3 of us are in the same course, which is basically one big group project. Naturally, since I'm close friends with our mutual friend, and having partnered with my ex on previous smaller projects before I assumed we'd all be on the same group. However, I was talking with my friend and she told me they are both already in a group, and that I'm not in because my ex doesn't want me there. I was pissed off for like 5 minutes and then dropped the subject.

I go talk to my ex in the hopes of figuring out what her problem with me is and fixing it so that situation doesn't happen again. She gives me the same runaround, gets all defensive and doesn't say shit, at which point I stop trying to talk and just lay into her (nothing vulgar, just confrontational). The conversation ends there.

The next day my friend texts me saying that I'm wrong about talking to her in the first place, we're not that close as friends ( we've been close for 5 years now), and that she looks at me differently now cuz apparently I'm the asshole, even though I'm the one who got fucked over now and 3 years ago.

So am I the asshole? If so what do I do? If not, what do I do as well?

I realize the whole thing may seem childish to some, it probably is. Just take into consideration that we're not actually adults.

confronting my ex 3 years on