Extreme measure or a dirty fantasy?

This young slut wanted to fuck, but her boyfriend's cock was still sore after a circumcision, so he offered her to fuck another dude with just one condition - he will be watching. Was it a spontaneous extreme measure or he's been having this dirty fantasy for some time already? He won't tell, but he came right into his pants watching his girlfriend get fucked from behind by some random guy they picked up on the Internet.