To most, the thought of their other half making love to someone else is unthinkable. But to Louisa Leontiades it's a pre-requisite.
When her marriage hit the rocks in 2007, instead of going to a marriage guidance councillor Louisa convinced her then husband to embark on a four-way relationship known as a quad, with another married couple. This took both of them on a dramatic journey with an ending that neither of them could have ever imagined.
Louisa put pen to paper and wrote a book on her experiences called The Husband Swap - she joins us today to tell her story.