For most, it happens by degrees. First, you take over managing the medications, appointments, the driving and cooking. Soon it’s the showering, the dressing, the getting in and out of bed. Then it’s dealing with the ablutions and the accidents.

Slowly – and then all of a sudden – the entire dynamic of your relationship has changed. You’re no longer just a spouse; you’re a carer. One who is on duty 24/7, likely with frailties and health needs of your own.

“The power dynamic changes,” says geriatrician Dr Cheryl Johnson. “Your whole focus becomes the person you’re caring for.”

And with that focus, Johnson says, the carers begin to neglect themselves.

There is beauty in caring for someone you love: love expressed through sacrifice. But ultimately, that’s a romanticised way of looking at it. It ceases to be beautiful when it becomes dangerous. If you collapse as the carer, there may be no one left to care for your spouse. In sacrificing yourself, you can end up placing both of you at greater risk.

“We don’t think about what those last years might actually look like,” Johnson says. “We tend to jump from now to assuming we’ll simply go to sleep one day and not wake up.”

The reality of the gap between now and then is often far uglier than that. Without proactively managing ageing, many will experience a slow, inexorable decline: mobility goes, memory falters, independence erodes.

You adjust and adjust and adjust – and what would have horrified you in the beginning slowly becomes normal. For many people, there comes a point when they realise they can’t keep going like this anymore, or a crisis forces a reckoning. Sometimes, that crisis provides the permission they may have been longing for: to make a change that probably should have happened much earlier. Either way, emotionally it’s a mess.

You feel guilty for feeling like you failed them or broke your promise. But there’s also some relief that you’re no longer carrying the burden alone. Then comes the guilt for feeling relieved.

It can become a vicious cycle – and it’s very common. Johnson tells the story of a woman caring for her husband with dementia. She did everything around the clock for years – until she couldn’t anymore. “She said to me, ‘I feel like I failed him.’”

From the outside, Johnson says it was obvious to see that she hadn’t failed, she had simply reached the limit of what one person can bear – but that doesn’t make the feeling of failure disappear.

So how do you cope with it?

“Reframing is a helpful strategy,” psychologist and grief counsellor, Dr Geraldine Tennant says. “You can reframe your thoughts about breaking the ‘in sickness and in health’ pledge by seeing that underpinning this pledge is a principle of protecting your loved one – you are protecting them by placing them in care and thereby honouring your promises and vows.”

Even though you feel guilty, guilt is not a good decision-making tool. You’re not choosing between “caring” or “not caring” – you’re just choosing a different kind of care, one that is better suited to the need.

Care facilities have trained staff who work shifts, get meal breaks, days off, time to rest and recuperate – whereas you are only one person.

Plus, being relieved of the relentless demands of caregiving may also allow you to simply be their spouse again – to sit with them, talk to them, hold their hand – rather than managing their healthcare.

There’s another emotion people don’t like admitting to in all this: resentment.

Not resentment towards the person themselves, necessarily – but towards the relentlessness of the situation. The exhaustion, the isolation, the loss of your own life. Because caring is supposed to be selfless, even thinking those thoughts can make you feel ashamed. Pretending they don’t exist doesn’t make them disappear, though. It just leaves you suffering quietly and alone.

With all of that going on emotionally, it’s no wonder the decision is usually made much later than it should be – once the need is urgent.

“They cope,” Johnson says. “And then there’s a crisis,” like a fall, that results in a hospital admission and a sudden need to find care, quickly.

Unfortunately, you can’t just stroll in from the street and secure a place in a rest home. There is a process – and it can take weeks, or even months to work through.

To give you an idea, you start with a Health NZ “Needs Assessment” that you or your healthcare provider can refer you for. It will cover things like your mobility, cognition, safety and needs, which will determine the level of care required – for example, home help, a rest home, hospital-level care, or a dementia ward. Home help may be subsidised, or you may need to pay privately.

If the answer is a care facility, it’s then your job to find an appropriate one – because not all of them can cater to all needs; availability is often scarce and some have wait times of up to six months. Layered over all of this is the financial reality that good care is expensive, and not everyone is entitled to public funding (there’s a whole separate article in that) or has the luxury of choice.

But the takeaway from the experts here is don’t wait until you’re drowning before you start the process – that will add to what is already enormous pressure.

If you’re reading this and thinking, “this is us”, or “this is my parents”, there are a few things worth remembering.

When you’re carrying too much, all alone, trusting others to help carry the load is the right thing to do.

Sometimes the right decision still feels heartbreaking but that doesn’t make it the wrong one.

Hannah McQueen is the founder and director of Age Brightly. She is also the host of The Next Bit podcast on iHeart Radio.