https://en.wikipedia.org/wiki/Wanderlust_(UK_TV_series)
Started out with some promise, but completely missed the opportunity to explore relationships that have developed into a sustainable model without the need for monogamy and instead refueled the mainstream assumption that "this can't work".
It was clichéd beyond belief and sometimes didn't even bother to fill in the gaps. So the story goes:
Long term married couple are bored with sex life.
Couple then agree to see other people
Find the experience immensely arousing and satisfying
Then. of course, feelings and emotions and love spoils the day
Couple splits up,
New relationships fall apart,
Everyone gets back together in the end
They also needed to throw in a traumatic event that triggered the initial breakdown ('cos no normal couple would ever contemplate such a thing)
It's like the effing thing was written by the Church of England marriage guidance club.
The only saving grace was the music.