Cathy had married Edgar, but she loved Heathcliff. She describes Edgar’s soul as being as different to hers ‘as a moonbeam from lightning, or frost from fire’. In her mind, she and Heathcliff are one, even though they will never be together, because their souls align.

This is just one of so many references in literature to the idea of soulmates. It’s a romantic idea that out there in the world is the perfect match for each person, the other half to make a whole; that as Rumi said, ‘Lovers don’t finally meet somewhere. They’re in each other all along.’

The origins of the concept of soulmates go back a long way, and in fact they aren’t all that romantic. It was the Ancient Greek philosopher Plato who introduced the idea of pairs of souls in his dialogue The Symposium.

In his story, humans originally had four arms, four legs and one head with two faces. When they angered the god Zeus, he decided to punish humans by splitting them in half and scattering the halves all over the world. Needless to say, the split humans were in quite a state, unable to thrive, and so the god of healing, Apollo, sewed them up. Now each human was whole in body, but not in soul, and would forever ache for the other part of his or her soul and search for their ‘other half’. Plato wrote:

‘… and when one of them meets the other half, the actual half of himself, whether he be a lover of youth or a lover of another sort, the pair are lost in an amazement of love and friendship and intimacy and one will not be out of the other’s sight… even for a moment…’

It wasn’t until 1822 that the word ‘soulmate’ was coined, by the English poet Samuel Taylor Coleridge. He wrote in a letter: ‘To be happy in Married Life… you must have a Soul-mate as well as a house or a yoke mate.’ Today, the word is in ordinary usage – but the experience of finding a soulmate is anything but ordinary.

In my latest novel, Concerto, for example, Umberto is staggered by the emotional connection he feels after making love to Catriona, the ‘raw, naked emotion that went beyond even the most intense erotic exploration, it had been the instinctive union of two souls’. A man who has been lost in despair for years since losing his sight and his will to compose music, he is transformed by the discovery of ‘the other half, the actual half of himself’.

Tied up with soulmates is the idea of fate, of destiny, and this is a theme I often explore in my novels. When you are two halves of a whole, will an unseen hand guide you towards each other?

In Aphrodite’s Tears, Damien tells Oriel: ‘Peprōmenon phygein adynaton, it is impossible to escape from what is destined, and I firmly believe that it is our destiny to be with each other.’ In The Echoes of Love, though, Venetia is sceptical: ‘One forges one’s own destiny,’ she tells Paolo, and, ‘Fate is for those too weak to determine their own destiny.’

To a certain extent I believe in fate, and I believe that some have the gift of second sight and can foretell aspects of your future. But having said that, I also believe that you make your own destiny. ‘Aide toi et le ciel t’aidera’ was a favourite saying of my governess: ‘Help yourself and heaven will help you.’

Thus, when it comes to finding your soulmate, you must put in the work, not only to seek him or her, but also, crucially, when you have found your other half, to recognise that and be open to reuniting.

This effort need put no one off the journey, because that moment of reunion is everything, everything. It is the very essence of romance, the moment to which all love stories build, but it is never the end of story; it is the beginning.