One of the best nights I have ever had was watching my wife get fucked hard by another man. I was sitting in an easy chair as an other man did what ever he wanted to my wife. While I was being serviced by my wife's best girlfriend. When he finished with her, I then had my way with my wife. A little later we both fucked my wife. He fell alseep with her, so I took the best friend to another room and fucked her again before calling it a night. 
Yes sloppy seconds is lovely, that's half the buzz for me, feeling her all wet and loose after others have been there immediately before me... Or a nice surprise when she creeps home after a night out with her mates and the cunt hole is well used and sloppy for you where she's done a bit of illicit fun with a guy or guy's she's picked up.