From the same article
It’s not just if a partner dies that cohabiting couples face a financial penalty. Research from Hargreaves Lansdown shows that getting married, and staying married, can provide a pretty substantial bonus.
Sarah Coles, personal finance analyst at the investment firm, explains: “The numerous tax benefits available to married couples means that even in cold financial terms, it may pay to tie the knot. In fact, over a 50-year marriage, even after the cost of the wedding, in today’s money, the couple could be £190,964 better off.”
The most obvious benefit is the marriage allowance, a small but constant perk specifically designed to reward marriage over cohabitation. It allows a partner who doesn’t use their full personal tax-free allowance to transfer a chunk of it to their taxpaying partner – up to £1,150 in the current tax year. That means a potential saving of up to £230 a year.
Married couples can also share assets between them and take advantage of both personal tax allowances, personal savings allowances and dividend allowances. They can reduce their capital gains tax liability on assets held jointly by combining their gains allowance.
On top of that, married couples can inherit their spouse’s ISA investments, without losing the tax-break on their cash. They benefit from defined benefit pension death benefits, meaning they typically gain 50 per cent of a deceased spouse’s pension.
Perhaps the biggest break for married couples comes from inheritance tax. A married partner can leave everything to their surviving spouse with no tax to pay, whereas unmarried couples would benefit from the normal allowances, but after that they are likely to pay 40 per cent tax.
What’s more, within a marriage the surviving spouse can also inherit their partner’s inheritance tax allowance, meaning they can leave £650,000-worth of cash and potentially £350,000-worth of property to their heirs tax-free.
That’s a massive benefit and it is not available to unmarried couples."