Review: The Slap, the 2011 Australian version
The Slap was a 2011 Australian TV series, and later an American one. Both were based on a novel by Christos Tsiolkas. I remember watching the American version a few years ago, but I think the Australian one is better. Melissa George starred in both. The Australian version is currently streaming on Hulu.
Toni Collette and Steven Mackintosh play Joy and Alan, a married couple who agree to indulge their Wanderlust, meaning their quest to find new and exciting sexual partners.