An extract from a biography about Emmanuel Macron has discussed how the aspiring president of France and his wife faced the ire of Macron's parents in a battle to continue their relationship.

The book, named Emmanuel Macron: A Perfect Young Man was penned by French political journalist Anne Fulda, and details how Macron met his wife, who at 64 is 25 years his senior.

Macron's parents detailed their shock at the burgeoning relationship between student Macron and his teacher at the time, Brigitte Trogneux.

"We couldn't believe it. What is clear is that when Emmanuel met Brigitte we couldn't just say 'that's great'," said Macron's mother.

After being questioned about his relationship, Macron has responded to critics of him and his wife's partnership, describing their love as "a lasting passion".

"It was at secondary school, through drama, that I met Brigitte. It was surreptitiously that things happened and that I fell in love. Through an intellectual bond, which day after day became ever closer. Then emerged a lasting passion," said the French presidential hopeful.

"I had to fight in order to live both my private and my professional life as I wish," Macron says. "I had to fight, and it wasn't the easiest nor the most obvious, nor the most automatic thing to do, nor did it correspond to established norms."

Ten years into his marriage with the former teacher, Macron said he still finds the judgement of his relationship difficult.

"It is very hard. An experience like that makes you think… You have to learn to fight for things, to bear the burden and have a life which does not in any way correspond to other peoples' lives.

"That was what we went through for 15 years. We managed to achieve the situation we're in today, because we knew it was what we wanted. It didn't just happen all by itself."

Leading sex therapist Bettina Arndt spoke to Sky News about the sexist and ageist responses to the pair's marriage.

"And we could draw all these conclusions from that particular behaviour, who knows? We don't know about that relationship? All it says, is that relationships are really complex and they've been married for 10 years," Arndt said. "And they obviously have something of lasting rewarding union there – and bully for them I say."

In spite of all of the interrogation under the spotlight, the couple are firm on keeping one thing private.

"Nobody will ever know at what moment our story became a love story. That belongs to us. That is our secret," said Trogneux in the book.