I was wondering if the implication was it was some sort of [straight] swinger party. With menage being the first part of menage a trois
1. (=nettoyage) housework
faire le ménage - to do the housework
une femme de ménage - a cleaning woman
faire des ménages - to work as a cleaner (in people's homes)
2. (=couple) couple
(=personnes mariées) married couple
se mettre en ménage avec - to set up house with
monter son ménage - to set up house
faire bon ménage avec - to get on well with
heureux en ménage - happily married
3. (Administration) (=famille) household