Almost half (40%) of Wesleyan advisers had also discovered secret debts, savings or pensions that one partner did not know about during a meeting.

Disagreements over lifestyle goals were the most common reason behind the arguments witnessed by the advisers, with a third (36%) of the arguments witnessed having this as the cause for tension.

One in five (20%) couples surveyed by the mutual thought their partner may have secret retirement savings, while 10% admitted to having secret savings themselves.

One in six (15%) thought their partner may have debts that they don’t know about or can’t say for certain.

Of the 2,000 married couples surveyed by Wesleyan, almost half (46%) did not have a retirement plan in place, with a third (31%) confessing to not having a clue how much money they will need in retirement.

Two in five (41%) of the couples surveyed had not taken independent financial advice for retirement, although 19% said they think it is something they need to do.

A quarter (25%) of couples confessed they feel awkward asking about their spouse’s pension and savings, whilst 10% said they have very different views on retirement.

One in five (20%) admitted they have not been honest with their partner about their retirement goals.

Linda Wallce, director of financial services at Wesleyan, said: “Couples absolutely should be able to keep private financial lives separate, but – as all advisers know – there are benefits to planning together.

“This can involve some difficult conversations between couples, who may not have been entirely transparent with each other about their finances.

“But a good financial adviser can work as a mediator, emphasising how not being open about your personal plans and finances with your partner can lead to financial and emotional trouble down the line.

“By working together, there are opportunities for couples to maximise their joint retirement income and achieve tax advantages, potentially by consolidating their pensions or other resources.”

Wesleyan surveyed 2,000 married UK adults between 16 and 24 October. The mutual also surveyed 64 Wesleyan financial advisers in October.