Very hot.
I often fantasize about a scenario like this.
We used to go to swinger parties a lot and I would love the idea of attending such a party with a chastity cage.
I get turned on by the idea that she would be free to have sex with anyone she wants while I would have to ask her permission to unlock me to play with other girls.
I imagine the embarrassment of telling a woman I want to hook up with that I need my wife permission and that I have to beg for the key (maybe while she is fucking someone!).
I guess my chances of having sex with the girl would be greatly reduced

Let us know how the party goes