<human>: Can you provide a brief overview of the text?

So, I've become good friends with my boyfriend over the past year, and we've been dating for about 5 months. He mentioned this girl he practically fell in love with, but never dated, maybe once or twice casually long before we were dating, so I never thought it to be that big of a deal. Basically, from what he's told me, he really liked her, "began to fall in love," and went through hell and high water to get him to like her. However, she rejected him and was a complete bitch to him afterward. He said she also told a bunch of people that he was a total creeper. This was about a year to a year and a half ago. But really, he talked maybe 5 minutes on that subject total. I figured he was okay now.

However, after we started dating, he began to make it clear that he was extremely angry with her. He referred to her as subhuman, and would always act extremely pissed off whenever he'd see her. He's friends with this guy who used to date her, and when she showed up one night when we were all hanging out, he said that just her presence killed the night. Whenever he'd her, he'd literally run away. He'd even talk about how he dreaded going to school or other events because of her being there. Really, she doesn't do anything now. She's pretty much forgotten his existence, but he still acts as though she's trying to ruin his life.

I've told him I think he REALLY needs to get over her, and that I don't want to hear him complaining about her because nobody wants to hear about their significant other bitch about a relatively harmless ex-crush, right? Anyways, he always will be like "okay, alright, alright," yet he STILL continues to do it. Is it even worth bothering about? Am I being selfish/unempathetic, or is this an actual problem? Reddit, what should I do about this?
<bot>: Boyfriend is still bitching about a girl from over a year ago that he isn't even dating. What to do?