Avivah Wittenberg-Cox has always been a feminist. Now, the 56-year-old coach, business lecturer and CEO of of management consultancy 20-first, says she’s applied her feminist principles to the arena of love. Why, she asks, should women settle for an unhappy or unfulfilling relationship just because they are over 50?

Seven years ago, she walked away from her 22-year marriage, feeling she was deeply unfulfilled and unappreciated. She “took the leap” and is now happily married to second husband, her “soulmate” Tim. In her new book, Late Love, she details her experiences and explores the trend for divorce and re-marriage in the over-50s. Part autobiography, part self-help book, part sociological study, it includes personal essays, creative writing and practical exercises for people considering whether it’s time to follow her lead.

She quotes anthropologist Margaret Mead’s theory that everyone has three loves during their lifetime: their first love, then their spouse and co-parent to their children, and finally their soulmate in full maturity. Some find all three in the same person, but most of us have at least two.

“I had always thought it was just a good theory, until it actually happened to me,” says Wittenberg-Cox. Her first love was a Frenchman in Paris, when she was a student; the second, her first husband, and the third, soulmate Tim. “I realised that Mead had described my life before I’d lived it!”

She is not advocating that people walk away from their husbands simply because they are tired of them. She believes in couples working together at a relationship. But some relationships are simply not meant to last forever, she says, they are only right for a particular time in our lives: “People accept that your first passionate love may not be the best match for having and raising children. So why can’t we accept that the father of your children may not be the kindred spirit with whom you dream of spending the 30 (or more now) years after the children move on?” she asks. “Why does moving from your second to your third love have to be so traumatic and difficult? Wouldn’t it be a good idea if we could make love contracts that were renewable, perhaps every 20 years or so?

“Once the children have grown up, perhaps it’s time to re-evaluate, to recommit and to redesign our relationships. After all, we accept the idea of lifelong learning, new careers and transformation in the workplace. We accept that nobody has a job for life anymore. Perhaps it’s time to accept it at home as well.”

Although her husband was unhappy about the split, she says they are now good friends. “One of the many reasons I left was that I did not think I was particularly good for my husband, nor that I made him happy. I truly hope that he finds someone who loves him better than I could,”

As for her young adult children, she says they have been “wonderful”, adding “one of my prime responsibilities to my children is to role model how to live lovingly, truthfully and fearlessly.

“It’s not putting yourself ‘first’, it’s realising that you will contribute your best to the world, and to everyone you care about in your life, if you are loved and loving.”

Women now have their own earning power, and people no longer die shortly after retirement. In both the UK and the US, in two-thirds of cases it is the woman who files for divorce. And, while both divorce and marriage rates have dropped overall, the greatest increases are seen in the baby-boomers. Like Wittenberg-Cox, many are deciding that “adequate” marriages are inadequate and that they’re not too old to find love again.

Born in Canada,she spent much of her life living in France, before settling with Tim in London. Her mother was a German-born Jew, who hid in Nice during the Second World War, before being denounced and deported. She survived Auschwitz, where she became friends with Simone Veil, and returned to Nice. It was there, at a Jewish fundraiser, that she met her husband, another German-born Jew, who had survived the Holocaust in Switzerland.

He was offered a teaching post in Quebec, so the couple moved there. “My poor mother,” says Wittenberg-Cox. “This Jewish Holocaust survivor suddenly found herself in Catholic Quebec in the 1950s. When my brother was born, she organised the very first circumcision in the hospital in Quebec City. The nuns had never seen anything like it.”

The family moved to Toronto, where Wittenberg-Cox grew up. “We were strongly culturally Jewish and pro-Israel, but not religious at all,” she recalls. “My father died of cancer at 36, so my mother took herself to university and became an academic, bringing us up as a single mother.

“She moved in very academic circles, with lot of other Jewish European emigres, but we were never really a part of the local Jewish community. It felt too small and I didn’t want to narrow my options and my friends. ”

She’s aware that being called Avivah is a “great signaller” of her identity: “All three of us children were given Jewish names. I find it a useful way of knowing who is Jewish. If someone recognises my name, they must be Jewish too!”

She has brought up her two children, whose father isn’t Jewish, in the same culturally-Jewish spirit. “They know they’re Jewish, what it means, their history. I’d say we’re proudly irreligious, which partly comes from living in France for many years, which has a particularly secular way of life.”

When she walked away from her first marriage she worried how her mother might react. In fact, she was very understanding and supportive. “Perhaps her experiences as a Jewish woman have something to do with this,” Wittenberg-Cox reflects. “She understood. Historically, Jews have been very mobile and not been as deeply-rooted in places, or relationships, as those who haven’t always had to be ready for the next wave of trouble, or to flee. That’s allowed us to be able to connect deeply with people, but not necessarily to expect the relationship to last forever. We form attachments easily, but we are able to detach easily too.”

Avivah Wittenberg-Cox’s Late Love was published this week by Motivational Press