Is OTHER wrong in the post ? POST : Context:
My ex and I dated for like a few weeks three years ago and then broke up because she was leaving to travel abroad. We both moved on, not a big deal. We ended up back at the same school about a year later and decided to just be friends rather than try and pick back up.
Fast forward to today, me and my ex are still good friends and she lives in the same building complex as me, so we hang out pretty often.
My girlfriend is pretty shy and has commented that she is afraid that I'm going to find someone prettier or less difficult and leave her. My girlfriend knows that I'm friends with my ex and that we hang out. They even met at a house party last month.

My question is, AITA for still being friends with my ex and hanging out with her without telling my girlfriend?