Simple!

It's completely true that some of us men just want sex only!
Yes, a loving relationship is fine, but I have found myself thinking of other girls I have fucked when I am fucking the present one? The same way I will probably think of her when I fuck the next one?
I think that it's fair to say that I remember the dirtier girls or, most importantly, the ones with whom I have randomly fucked and emptied my spunk in, never to be seen again.
At one stage, I fucked several of the married women in my local pub and we enjoyed it - the one in particular - Hayley - was beautifully dirty although I never got round to sodomising her, for some reason?
Feeling one's spunk pumped deep inside a willing girl or onto her upturned face, is wonderful, as long as it's just NSA! Mmm!