Sometimes it is like that first attempt to harness a hydrogen balloon to a fire balloon: do you prefer crash and burn, or burn and crash? But sometimes it works, and something new is made, and the world is changed. Then, at some point, sooner or later, for this reason or that, one of them is taken away. And what is taken away is greater than the sum of what was there. This may not be mathematically possible; but it is emotionally possible. After the Battle of Abu Klea there were ‘immense hordes of dead Arabs’, who were ‘by necessity, left unburied’. But not unexamined. Each had a leather band round one arm containing a prayer composed by the Mahdi, who promised his soldiers that it would turn British bullets to water. Love gives us a similar feeling of faith and invincibility. And sometimes, perhaps often, it works. We dodge between bullets as Sarah Bernhardt claimed to dodge between raindrops. But there is always the sudden spear-thrust to the neck. Because every love story is a potential grief story. Early in life, the world divides crudely into those who have had sex and those who haven’t.