Not stroking my ego or anything, everyone is attractive to someone. I also know I'm not the only one that experiences this. Sociology/psychology is a hobby of mine so I would guess that the reason is more of an animalistic urge/instinct to let the "best sperm win"

It sounds weird but it's a fact that seeing another dudes junk in a sexual context, especially with a girl you're fucking, makes you bust way more of a load. Literally to "flush out the other dudes sperm"

Do you think it's something as simple as when a girl is Fucking one dude, she loves it and wants to fuck even more? Where as single girls have a rather more dormant/mild libido?

Or maybe it's cause she already has all the emotional support from her partner and just wants some casual man meat?

Curious as to what you guys think.