I don't know about you guys, but I broke mind down as a bit of psychological complex. (If you can call it that.)
For me, it's the power play that comes into affect when another male essentially asserts dominance in your own territory.
I simply enjoy watching the sexual aspect being blended with a sudden and abrupt power shift - the kid getting cucked by his bully; etc. That also translates to stories where the wimpy kid cucks the bully, or a best friend comes into play.
There's a bit of a sadistic enjoyment I get out of watching emotional disarray that blend with the sexual touch to this fetish that hits me hard. I almost always myself actually encouraging the emotional pain that often plays as a companion to the fetish. The main exceptions are when I have to go into the victim role now; I had this fantasy happen between a friend and my mother, and after weeks of it, I got sick and tired and lashed out.
The fetish still remains, but I've realized it's amusing until I get involved - the idea of others suffering really does get me riled up, even if I will never allow that same thing to happen to me again.
I think it falls under a form of sexual psychopathy, if that shit is even a thing. I'm not sure, so don't think I'm trying to be edgy here.