<human>: Can you condense the text into a few key points?

This happened last weekend and I'm still in complete shock about it, I genuinely couldn't feel worse about it if I tried. So to add context basically I had a huge breakup with an ex girlfriend recently and she has immediately moved on with another guy, who has not hesitated to absolutely roast the shit out of me and make it clear he doesn't like me behind my back (I broke up with the girl and she took it extremely badly). 

Anyway me and my mates got tickets to this gig last Saturday which we had all been looking forward to for a long time but then one of my friends gets word that this guy is also coming to the gig with all of his friends. Not only this but he has apparently said that if I turn up he will I quote 'not hesitate to beat the shit out of me'. Even though I don't like turning my back when challenged, I just really didn't want anything to do with this girl so I decided not to go. However my friends insisted I went and said they'd have my back the whole evening, so reluctantly I go.

I'm really not the fighting type either and confrontation isn't my thing. Bare in mind this fucker is about 6 foot 4 and pissed off so I wasn't massively excited about meeting him. To calm myself down I thought I'd go for a drink which became several and I was, at this point, fucked. I spent the first two hours of the gig by the bar scouting the crowd whilst my mates where enjoying the music.

Then I feel a large hand on my shoulder, firm grip and a deep voice call my name. Without hesitation I swing round with a vicious right hook and pop this guy straight in the face. Only to my horror it isn't the new boyfriend at all, it's one of my old teachers from college, now sprawled on the floor completely KOd. 

The boyfriend and his mates never even turned up.

I went with the teacher to hospital and explained the situation and he was sort of fine about it.
<bot>: ex's roid rage new boyfriend threatens me and says he's coming to fuck me up, I get really drunk, knock out old teacher by accident, boyfriend never even turns up.