They had been friends since school, they'd always had a relationship like that: it only looked a little flirty from the outside, but really they were more like siblings, definitely absolutely nothing more than friends. She was so upfront about it that I completely believed her and therefore ignored all the warning signs.

Looking back, it was so obvious. They weren't even hiding it. They were all over each other, from jokingly spanking her ass to betting him he couldn't bench press her. Right in front of me, my friends, her friends, us all (including myself) laughing and smiling along as they showed off their chemistry and compatibility.

He was a good looking guy. Taller than me, more muscular. I'm slim, good looking, a little bookish. He was more how you might imagine a gym bro, and not much smarter than that either. But I had nothing to worry about. They were just old friends. She wasn't even remotely into guys like that anyway.

Hence I didn't have any qualms when they went on holiday together (with 3 other friends), nor when they shared a tent together at a festival. We had only been there were a couple of months in between her and my tenancies ending so it made sense she moved into his spare room because my old apartment was so tiny and crowded. When we did move in together, of course he came over to watch a movie and have take out when I was away with work.

I'd been out of the city on my birthday to see my family. What a present I received when I got home. I wasn't even particularly earlier than planned. She knew. She wanted me to come home on my birthday to see my girlfriend getting pounded by the guy she told me not to worry about on my own bed.

What did they do? Did they rush to cover themselves up? Start making excuses and apologising? No. They just carried on.

And wat did I do? Did I fight him? Start screaming and shouting? Storm off? No. I just started.

I could feel the burning embarrassment and humiliation of being emasculated in such a cruel way. And yet I could also feel myself getting painfully, shamefully hard.

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