They were involved in a menage a trois relationship.
menage a quatre
Frequency:
65
%
The party turned into a menage a quatre with unexpected guests.
menage a cinq
Frequency:
40
%
The band members formed a menage a cinq to collaborate on new music.
Idiomatic Expressions for menage
Phrase: menage a cinq
Meaning: a sexual relationship or arrangement involving five people
Usage: The reality show featured a group of friends who decided to experiment with a menage a cinq.