"Throughout most of our history, people survived for a maximum of 35 years. Staying alive was a full-time job, and most pair-bonds ended with one partner dying. Given this lifespan, at least 50 per cent of mating alliances would have ended within 15 years. This figure is surprisingly close to the current global median duration of marriage, 11 years. It seems unlikely that natural selection equipped us to keep relationships lasting much more than a decade. [...] One promising route is to consider the advances in neurobiology and see how we might use science. Some of the latest research suggests we could tweak the chemical systems involved to create a longer-lasting love".