The unique story behind French presidential hopeful Emmanuel Macron's love life

When the results in the first round of France's presidential election showed that Emmanuel Macron had made it to the runoff vote, his wife Brigitte Trogneux, stood next to him as the smiling couple waved at supporters.

The two have been married for 10 years and they have known each other since 1992 when they met in school. Sounds like a typical 'childhood sweetheart' romance, but there is a twist to this tale.

Trogneux is 25 years older than her husband and was actually his teacher when a then-teenage Macron attended a private Jesuit school in Amiens, northern France.

According to the Daily Mail, Trogneux - then a married mother-of-three - was the teaching supervisor for the school's drama club. Macron, who loved literature, acted in the club's theatre pieces and grew closer to his teacher after convincing her to write a play with him.

When he was 17, he made a startling promise to her. "Emmanuel said to me, 'Whatever you do, I will marry you!'," Trogneux recalled in a magazine interview last year.

When Macron's parents found out about the pair's growing relationship, they were stunned, having thought that Macron might have been interested in Trogeux's daughter Laurence, who was in the same class.

They then tried to put a stop to the romance by insisting that he complete the rest of his secondary education in Paris, Britain's The Independent reported. That, obviously, did not work.

The pair kept in contact and Trogneux eventually left her previous husband and went into a relationship with her former student. "Little by little, he overcame all my resistance in an unbelievable way, with patience," she reportedly told a television documentary.

Since tying the knot in 2007, the couple has decided not to have any children together, website Heavy.com reported. Nevertheless, Trogneux does have three children from her previous marriage and also seven grandchildren, which makes Macron a 39-year-old step-grandfather.

The unconventional romance has fuelled speculation that Macron might secretly be gay, but Macron laughed off the rumours at a party event earlier this year, The Telegraph reported.

Macron qualified for the second round of France's presidential election after winning 23.75 per cent of votes in the first round, according to Reuters. In the runoff vote, he will face far-right leader Marine Le Pen. If he wins, he will become France's youngest-ever president.

A former banker, he served as the economy minister under the current presidency of Francois Hollande, before quitting to launch his party En Marche! (On the Move!), a progressive political movement last year.

seanyap@sph.com.sg