Cathleen O’Sullivan and her family need to decide which country to make their permanent home as bills begin to pile up

Cathleen O’Sullivan lives a dual life. For the past 3.5 years, Ms O’Sullivan, 42, her son Harry, four, and occasionally, her husband, Ray, 48, have been dividing their time between their London home and Ms O’Sullivan’s native Germany – usually flying back and forth once a month.

But the arrangement, which was originally put in place so the family could get a feel of how day-to-day life in Germany might suit them if they chose to move there permanently, has become exhausting – and expensive.

Now, says Ms O’Sullivan, it’s time to choose – but it’s not an easy decision to make. A self-confessed Anglophile, Ms O’Sullivan says she has felt drawn to both the UK and Ireland since she was 15, reading books about the countries and listening to music from bands like The Cure and The Smiths.

She eventually made the move to London in 2010 when she was 27, and excelled in a high performing HR career, before retraining as a career and leadership coach and setting up her own business. In London, she met Ray, who now runs his own plastering business.

The family on a desert safari recently. They have tasked themselves with making a decision by next spring, when young Harry must start school in the UK should they stay here

“The UK and Ireland are my big loves. It’s like you fall in love with a place that has helped you become the person you are,” Ms O’Sullivan tells The i Paper. “I have never felt more like myself than during my time in London. It has been the best time of my life.”

But the O’Sullivans currently pay rent on two flats – £1,750 for a two-bedroom flat in the north London suburb of Golder’s Green, and around £1,800 a month for a three-bedroom flat in Leipzig, a small city about 100 miles south-west of Berlin.

Harry, who has deferred starting school in the UK by a year, also attends part-time kindergarten in Germany, at a cost of around £390 a month for attending on a half-time basis.

The family covers their rental costs by renting out properties they own in the UK. For example, a house they own in Surrey generates £2,450 a month in rent.

When the O’Sullivans are in Germany, groceries are noticeably cheaper – with a weekly shop coming in at around £60, compared with the £120 they spend when they are in the UK. They also notice a difference in their utility bills: £100 a month for gas and electricity in London, compared with around £60 a month in Leipzig.

While children in Germany typically do not start school until they are six, they are not required to wear a school uniform. Many schools also offer after school care at a low or no cost. And all parents, regardless of income, receive a child benefit payment in Germany. Ms O’Sullivan receives around £113 a month.

Health costs are higher in Germany, though, with residents required to pay for their own health insurance, or face fines. Ms O’Sullivan, considered a resident because of the amount of time she spends there, pays around £550 per month.

The family also opts to pay for their own private health insurance in the UK, at a cost of £280 per month, so they can access services more quickly.

But they acknowledge it’s becoming unfeasible to continue shelling out double the expenses, and have tasked themselves with making a decision by next spring, when Harry must start school in the UK should they stay here.

“Ray started building a property portfolio early in his life, so that helps. Currently, though, we’re just making things work, so we want to start thinking about how we can invest that differently and build for the future,” says Ms O’Sullivan.

“[The way we live] is, on the one hand, a real luxury that we have, that so many people couldn’t afford. But on the other hand, he’s [Ray] approaching his fifties, I’m approaching my mid-forties. This money has to go somewhere else.”

Comparing the O’Sullivans’ living costs across the UK and Germany is not necessarily straightforward, as costs are not like for like across a capital city like London and a smaller city like Leipzig, and private health insurance is not mandatory in the UK. On the whole, though, Germany wins out due to the lack of school uniform and after school care costs.

The couple have also been using some of Ms O’Sullivan’s coaching techniques to help make their decision, like analysing their values, and mapping out their ideal life around factors such as time spent with each other, social networks, family connection, finances, health and wellbeing; and rating each location on both.

There’s also another key factor pushing the O’Sullivans in the direction of Germany. Ms O’Sullivan’s parents are there, while Ray’s parents have passed away. Her sister, who is also in her forties and has young children, is also there.

Ms O’Sullivan runs her coaching business remotely, and Ray can be based in Germany for his business once he expands his team appropriately.

“In Germany, my family is around the corner. It’s just so beautiful to see that relationship with our tiny human that they only were able to meet for the first time after he turned one,” says Ms O’Sullivan.

“I’ve come to realise how much I miss my family, and how much I miss the moments we have together. I want to be able to have regular chats with my mum and learn more about how she did things (when we were growing up).”

Another concern for Ms O’Sullivan is what she describes as the UK’s changing culture.

“Germany used to feel cold and not as open as the UK. But the UK now feels more polarised and the country I have loved since I was 15 doesn’t feel the same any more,” she says.

“But if we leave, it will feel like a break-up. I’ve never stopped loving the UK. The beauty of the country and people and their openness, and the humour British people still find in the midst of crisis, is for me, something tremendous, and something I think Germans can really be inspired by.”