Is AUTHOR wrong in the post ? POST : 3 parties here. Myself, the boyfriend, and the girlfriend. We'll call the boyfriend Y, and the girlfriend K. The friend in question is K.

I met Y and K in first year of university, when they were both single, and had what I think was a pretty good friendship with both of them individually for about a year before they started dating.

They saw each other for about four years, seeing each other through graduation and eventually getting an apartment together. This is through our undergrad years (still quite a developmental time). They were easily two of my closest friends as individuals.

Breakup context: K started a new program at school, with which came a new set of friends. Y's work had him out of town for weeks at a time, so K is often at their shared apartment on her own. Relationship appears to get a little rocky. The distance and time apart seems to be doing nobody any favours.

One of the new friends K meets is a guy that she gets close with, call him M. I hear from K that M has a poor opinion of K's boyfriend Y (my friend), and their relationship. M's comments appear to be regular. I hear all this from K, and tell her at the time that those sound like red flags of someone who's trying to split a couple up so he can slot in. M has admitted to doing exactly that before. Y is obviously in arms about the whole thing.

About 4 months into this arrangement (shared apartment, new job and new program) things come to a head and K calls it quits. It's messy because they're in the middle of the lease, and it's taxing on everyone. K and Y can both be stubborn and argumentative, and that's the side that comes out.

I had a suspicion that M was the driving force behind K breaking up. This is just from how K has described M to be. Without any evidence I gave K the benefit of the doubt and tried to be as supportive as I could to both K and Y.

I see Y often and we talk as often as we normally do. Communication with K drops off a cliff. Months later, I heard that K and M hooked up very soon after the breakup (approx 1 week).

I think I enough for me to say K ignored the red flags we showed her months ago, and purposely played right into M's hands, hurting my friend Y in the process. So I decide I'm not interested in hanging out with K anymore (not a big deal, since she's cut me off anyway).

A couple of years later, they're broken up and I hear through the grapevine she's apologetic and wants to reach out again. Our other mutual friends are all closer with Y than K, or vice versa and that dictates their opinion. I'm trying to stick to my guns. 

I'm in her town this weekend with some mutual friends for an unrelated reason, and this is affecting our plans (some want to catch up with her, some don't care... And me).

Reddit, AITA for not wanting to get together? Am I being self-righteous? Should I care this much?