‘Some therapists believe there are times when an affair can rescue a marriage, and even make it stronger,’ Amber counselled as we sat down to breakfast. ‘It’s not about assigning blame, but finding out the root causes of the infidelity so you can improve your relationship from the ground up.’

By the time our cappuccinos arrived she was more pragmatic. ‘Sometimes I wish Scott would have an affair. Then I wouldn’t have to have sex with him so often!’

‘Don’t get sad or mad, get bad,’ was Emerald’s advice. ‘After marriage, a cougar needs to be rehabilitated and released back into the wild. Let me lead you astray. Leave it to Diva!’ She laughed.

To alleviate my Harry-induced despondency, both sisters were determined to distract me, but in very different ways. It was a tug-of-love. While Amber liked to work hard at having a good holiday (attending Cardio Combat sessions, spin classes, acro-yoga, tango lessons and ‘enrichment lectures’ where she sucked up information on the Pacific’s cultural and historical aspects like a human hoover), the only thing Emerald wanted to work on was her tan.

‘Come join me in the jacuzzi for a cocktail, Rubes,’ she tempted. ‘I usually need a holiday to recuperate from my holiday, but on a cruise you just go with the flow. Literally. I’m just sitting back, drinking it all in – while drinking. What’s not to love about that?’

On the drive to the departure terminal at Circular Quay, Emerald had predicted that a cruise would be like a three-week wedding reception, complete with notoriously bad band. ‘The promotional brochure may promise the “new Beatles”, but what that means is four frickin’ Ringos,’ she’d moaned. But it had taken only one day for her to be converted.

‘No. Ruby’s coming to a photography class with me, aren’t you, Rubes?’ Amber had been equally critical of cruising. For the duration of the taxi ride to Circular Quay, she’d predicted the worst. ‘I’ve heard too many horror stories – the salt, the sand, the exotic insects – and that’s just in the sandwiches!’

But it had also only taken about a day for Amber to eat her words – well, she would have eaten them if she wasn’t too busy devouring the gourmet tucker. ‘I’m comfort eating, clearly. It’s the only time I stop worrying about you, Ruby. The chefs really need to install speed bumps to slow down my progress to the buffet,’ she’d said between mouthfuls of marinated crabmeat gateaux, tournedos of black Angus beef and waggles of lobster tails.