Wife sharing....

I have a question to husband's that share their wives with other men who have big cocks, especially BBC.

What emotion does the husband experience watching another man with a bigger cock fucking thier wife?
Is it watching and listening to her make noises that she's never made before with you?
Is it watching the act being performed?
I mean I don't know how I would react to someone else dicking down my wife to submission while I watch?
It's something that I am interested but scared at the same time.
I just want to hear what satisfaction they get.
I am not here to judge, it's something that I find so intriguing and would love to hear more about it.

I hope to hear from some people. Enjoy yourselves everyone.