Me and the Missus go swinging

As we entered our 50s the Missus and me found our
sex life waning.
There was no way we wanted to split up, as we liked
each other's company. After an incident at a hen night
she attended, we came to reassess our situation, and
decided that we could revive our sex life by going to a
swingers' group.
This is my account of how this happened.