The watcher.

I was always keen to watch my wife with another guy, it used to be I had to join in but the longer we did it the less I felt the need. I't wasn't that I wasn't into threesomes anymore it was I got more turned on by watching and having sloppy seconds at a later time.
Case in question Steve young guy in early twenties hung like a horse, nothing in common with me except loved fucking Anne if I joined in he felt self conscious and didn't perform as well. Steve used to prefer to come round if I was away from home on business according to Anne he would romance her then carry her to our bedroom and fuck her silly for hours at a time, if I was there he would drop round for a quick fuck and be gone in an hour or so. He also used to drop round to Anne's office when she was working late and fuck her over her desk amongst other places, also nearly broke photo copier copying them fucking while sat on it, not best photo copy.
But if I was there it was best if I hid and watched that way we all enjoyed ourselves and I got sloppy seconds.
Had another guy who loved being watched as he fucked Anne got as turned on as I did he used to change positions to give me a better view and encouraged me to guide his cock in when his hands were occupied with the rest of her body. With Anne's permission he once invited one of his friends round as well and I got to watch them taking it in turns with her from a chair six feet from the bed, that was one time I felt like a real cuckold and I got sloppy thirds after they left.
I think I watched Anne with twenty plus guys without joining in most times hidden other times just feet away all very enjoyable.