Many couples do not share a bank account. Some claim to be blissfully unaware of their partner’s penchant for purchasing campervans and coffee machines.

But, in all seriousness, do you actually know how much (or little) your partner has stashed in their pension?

In my experience, most couples don’t know the size of their personal “pensions gap”. Most of us have a ragtag collection of pensions from previous jobs and millions of people have lost track of one or more of these. But the higher earner is likely to have the lion’s share of the pension savings — especially so if the couple have children.

The person with the smallest pension is almost always a woman. It’s not always the case — I am an exception to this rule — but raising a family weighs more heavily on a woman’s lifetime earnings potential.

The associated “gender pensions gap” means that by the age of 55, the average manh as amassed a pot that’s nearly twice as big as the average woman’s.

You might think: “Well, if one of us has an OK-sized pension, we’ll muddle through.”

But there is a powerful case for the higher earner paying into what can be one of the family’s most neglected financial assets — the lower earner’s pension.

Yet, even if couples wanted to do so, there’s a big reason why they wouldn’t: tax relief. If the higher earner can enjoy higher- or additional-rate tax relief on their own pension contributions, why fund contributions for a lower earner, who may only get basic-rate relief? As millions more workers are dragged into higher-rate tax bands, this issue will intensify.

It’s an even worse deal for non-earners. The higher earner can pay a paltry £2,880 per year into their pension (topped up to £3,600 with tax relief). Introduced in 2001, this threshold has scandalously never increased with inflation. If it had, it would be around double this level by now.

Sir Steve Webb, the former pensions minister and partner at pension consultancy LCP, has a bold request for the new chancellor: let’s change pensions policy to make it more attractive for couples to even out their pension saving by making higher-rate tax relief transferable.

“We don’t need yet another report on the gender pension gap, we need some action to close it,” he says.

Changing tax relief rules to incentivise higher earners to divert pension savings into their partner’s name is one of the only meaningful ways to close it. Crucially, this would benefit couples that stay together, and those who split up.

“It is far better for women to have decent pensions in their own right while part of a couple than to hope that pension sharing after a relationship breaks down will do the job,” he says.

Webb is urging the government’s Pensions Commission to consider the dramatic rise in the number of single pensioners. The number of divorced over-65-year-olds has trebled in the space of two decades (see chart). Technically, pensions should be part of divorce settlements, yet only 13 percent of divorcing couples consider pensions in financial settlements, according to L&G.

In fact, solicitors tell me the new “no-fault” divorce rules discourage couples from pursuing the admin hassle of a pension-sharing order in their desire to achieve a quick uncontested split.

But that’s assuming you’re married. The number of cohabiting adults has nearly doubled to 5.4mn over the past two decades. Nowadays, nearly 15 per cent of all couples who cohabit are over 50, up from just 2.6 per cent.

Solicitors tell me that when relationships break down, older women in this position are flabbergasted to learn they’re entitled to nothing from their partner’s pension or future earnings (the myth of the “common-law partner” has a lot to answer for). The government recently launched a consultation into this problem, but that won’t yield quick results. Webb notes that pensioner poverty is rising fastest among the divorced and those who have never married, and women are the worst affected.

Changing tax relief to incentivise couples to build up pensions more equally while they are together would help to address this, but why would any chancellor agree?

“The question to ask is, what would happen otherwise?” Webb argues.

If one half of the couple benefits from the tax relief that the other half would have received anyway, there’s no additional cost to the taxpayer. And if the lower earner ends up with a much better pension, they’ll be less likely to claim means-tested benefits in future should the couple split up.

But even if you are married and stay together, another emerging risk is that your future pension could die with your partner.

The person whose name is on the pension is solely responsible for deciding how this money will be invested or accessed. Presently, record numbers of retirees are trading their defined contribution pension pots for annuities, but two-thirds of those sold are single-life policies. Buying a joint-life policy would leave a widowed partner with an income after the policyholder dies, but many shun this as it reduces the amount of income paid out every year.

All of the UK’s big workplace pension schemes are currently designing “default” retirement journeys for members who do not make an active choice when accessing their pots. Many industry watchers fear that if single-life annuities become the default, the potential damage to women’s pension prospects in later life will be even more acute — something that must not be allowed to happen.

We may wait in vain for policymakers to address any of these risks. So, here are three basic things couples could do this weekend to boost their joint pension prospects.

First, check your state pension forecast — if the lower earner has missing years of national insurance contributions, it could be worth paying to top these up and boost their state pension in retirement.

Second, if they work, they should email HR to ask if their employer will match any extra workplace pension contributions (this is worth doing even if they only get basic-rate tax relief).

And third, make sure you’re each other’s “nominated beneficiary” on all of your pensions. This takes less than a minute to sort on most workplace pension apps, but considerably longer if one of you dies without doing so.

Pensions might not sound like the most romantic of topics, but there’s a lot to be said for caring about a more secure retirement for your partner.