Imagine the scene. Former bachelor buddies Paul McKenna and Simon Cowell sunning themselves on a Barbados beach, permanent partners in tow, Simon playing happily with his young son Eric, McKenna cooing in the background over the apparent domestic bliss.

Still tanned from his holiday and recalling the scene now, the irony isn’t lost on multimillionaire McKenna, the 51-year-old newly-engaged self-help guru and hypnotist, who used to think relationships weren’t for him.

“I said to Simon: ‘Two years ago, who would have thought we’d be sitting here and you’d be playing with your son Eric and your two dogs?’ I’m so happy.”

Meeting McKenna at his mews house in desirable Kensington, it’s clear his recent engagement to Kate Davey, 43, his personal assistant of 20 years, has given him even more of a spring in his step, as has his latest self-help book The 3 Things That Will Change Your Destiny Today!, introducing ‘Havening Techniques’ which include lateral eye movement and rubbing your hands up and down your arms, in a sort of maternal hug.

They’re designed to unblock trauma and stress from the past and promote positive thinking. They certainly seem to have helped clear his own lasting blockage, namely commitment phobia.

“I’ve always really liked Kate, but she’s my assistant. Of course I fancied her, but it just didn’t seem appropriate.”

Kate’s former fiance had died suddenly, around the same time that McKenna’s father Bill died a few years ago, and neither of them were in a good place, he recalls.

“Then one night, Kate and I had a couple of glasses of red wine and I said to her: ‘Tell me something about you that I don’t know’, and she said: ‘I love you’.

“I said: ‘I love you too’, but she said we couldn’t do anything about it because we work together and it wouldn’t seem right’.”

So very properly, he took her on a date – and things progressed from there; 18 months on, they’re engaged.

“At first, it felt very naughty and clandestine. She didn’t want to tell people. Some people have been very happy for me.

“Kate’s beautiful. She understands me very well and I find that liberating. I was on an endless pleasure quest when it came to relationships, but now I’ve found something that’s fantastic.”

He took a little time off in October to take her on a romantic weekend along California’s Pacific Coast Highway, recalling how he went down on one knee to pop the question.

The wedding will take place this year in Buckinghamshire. They haven’t set a date yet, but it’s bound to be awash with celebrities.

Davey, a pretty, down-to-earth blonde, shies away from the media spotlight but says it upsets them when critics make extremely personal attacks on her husband-to-be.

She tells me McKenna is really intelligent and that, at the end of the day, all he wants to do is help people. I’m sure he’s more than happy to live a millionaire’s lifestyle too.

They live together at his luxurious house in Hollywood, although she’s kept her apartment, where she returns to when she needs some space.

“We still socialise with friends, but staying in is the new going out for us. We love watching Game Of Thrones and Peaky Blinders,” he says.

“I honestly thought I would never find love. I just thought it wasn’t for me. I’ve been in relationships that have lasted a few months and was in one which lasted a few years, but I wasn’t very happy.”

Cowell, who McKenna has known for 20 years, will be organising the stag do. “We’ll just have a curry and go go-karting,” the hypnotist reveals. “He’s like an older brother.”

The man who has reportedly sold more books than any other non-fiction author in the UK, including I Can Make You Happy/Sleep/Thin/Rich), says the latest techniques he writes about helped him through clinical depression, particularly when his father died.

“I also lost a number of friends and was working with people who were depressed, and I got infected by their mindset,” he reflects.

“I went through periods where I thought: ‘If I have a bigger house or more money, then I’ll be happy’. But that’s pleasure, not happiness.” I want to tell him I’d settle for pleasure.

“Happiness is the backdrop to our life,” he continues. “Much as I love a consumers’ society, which is what we live in, it’s set up to continually show you what you don’t have.”

“Being engaged has changed me. It feels different. We’re committed,” McKenna says. “When we’re married I can’t wait to say: ‘My wife...’ It’s so grown up.”

  • The 3 Things That Will Change Your Destiny Today! by Paul McKenna (antam, £12.99)

Book reviews

The Girl On The Train by Paula Hawkins (Doubleday, £12.99) Like many commuters, every day Rachel distracts herself on her journey to and from work by indulging in fantasies about the lives of the people whose houses she peers into from the safety of the train.

Unlike most commuters though, Rachel develops a morbid obsession with a couple she passes every day, a couple who just happen to live a few houses down from where she used to enjoy domestic bliss with her ex-husband Tom.

Fuelled by many gin-and-tonics, our protagonist revels in fantasising about the couple’s perfect life, until one day she notices something untoward. When the perfect wife is reported missing a few days later, Rachel feels compelled to get involved, with predictably sticky consequences.

This is a fast-paced, clever thriller which grapples expertly with the reality of alcoholism and loneliness, a cut above the current crop of psychological thrillers featuring girls in peril.

Anita Chaudhuri

The Winter War by Philip Tier (Serpent’s Tail, £12.99)

First-time novelist Philip Tier comes from the same ancient community of Swedish-speaking Finns as illustrator Tove Jansson, best known for the Moomin books. But though some of the Moomin characters make a brief and troubling appearance in The Winter War – they are the star attractions of an imaginatively sterile children’s show on board a Baltic ferry – the two writers couldn’t be more different.

The luminous northern light of tradition has been banished to the margins of this funny, sharply observed and very readable tale of a middle-class Helsinki family going slightly mad during one of Finland’s long, ferocious winters.

The book’s cover blurb suggests that it will blast away our preconceptions of Scandinavian society. But since the protagonist is a university academic who wrote an often-quoted study of Finnish sexual habits, and since one of the factors in the slow collapse of his marriage is a proposed kitchen redesign – really, not so much.

Liz Ryan

Book chart

Hardbacks

1 Girl Online by Zoe Sugg

2 Diary Of A Wimpy Kid: The Long Haul by Jeff Kinney

3 Minecraft Blockopedia

4 Lamentation by CJ Sansom

5 Guy Martin: My Autobiography

6 The World of Ice and Fire by George RR Martin & Linda Antonsson

7 H is for Hawk by Helen Macdonald

8 The Churchill Factor: How One Man Made History by Boris Johnson

9 Awful Auntie by David Walliams

10 The Sunrise by Victoria Hislop

Paperbacks

1 The Miniaturist by Jessie Burton

2 Elizabeth is Missing by Emma Healey

3 Station Eleven by Emily St John Mandel

4 Happiness by Design: Finding Pleasure and Purpose in Everyday Life by Paul Dolan

5 The Bees by Laline Paull

6 The Guest Cat by Takashi Hiraide

7 Davina’s 5 Weeks to Sugar- Free by Davina McCall

8 Do No Harm by Henry Marsh

9 We Are All Completely Beside Ourselves by Karen Joy Fowler

10 Gone Girl by Gillian Flynn

Chart supplied by Waterstones in Brighton