Can you get a postnup after years of marriage? Yes – you can make a postnuptial agreement at any point in a marriage, whether you are one year in or forty, and plenty of couples do exactly that. There is no rule that a nuptial agreement has to be signed before the wedding; a postnup exists precisely so that married couples can put the same clarity and protection in place afterwards. If life has changed since you married – and over the years it almost always does – a postnup is the tool that lets your financial arrangements catch up.
This guide explains why couples make a postnup long after the wedding, how the process works, whether an agreement signed years later still carries weight, and the limits that always apply. If you are new to the idea, our overview of postnuptial agreements in the UK is a good place to start, and the prenup vs postnup comparison shows how little separates the two.
Is it ever too late to get a postnup?
No. There is no deadline and no expiry point in a marriage after which a postnup becomes unavailable. Couples make one a few months into married life and couples make one after thirty years together. What matters is not when in the marriage you sign, but how you go about it – that both partners disclose their finances honestly, agree fair terms, take their own advice and sign freely. Get those right and a postnup made two decades in stands on exactly the same footing as one made in the first year.
Why couples make a postnup later on
Life rarely stands still, and a postnup is a way to bring your agreement into line with where you actually are now. The most common triggers include:
- An inheritance or family gift – you want to ring-fence money from family so it stays with the partner who received it.
- Starting, growing or selling a business – a company that did not exist when you married may now be a couple's most valuable asset, and one you want to protect.
- Buying property – a new home, a second home or a buy-to-let can shift the whole financial picture.
- A significant change in one partner's wealth – a windfall, a promotion, share options or a pension that has grown substantially.
- Children arriving – often a moment when couples want to set out how they will provide for each other and, in a blended family, for children from before.
- A simple wish for clarity – the conversation you never had before the wedding, now that there is time and space to have it calmly.
In a second marriage these reasons often stack up together, which is why postnups are especially common where one or both partners bring assets, a business or children into the relationship.
How a postnup works after years of marriage
The process is the same whenever you make one, and it mirrors how you would get a prenup. The steps that give an agreement weight do not change just because you are already married:
- Talk it through together. Agree why you want a postnup and roughly what it should cover, approaching it as a joint plan rather than a demand.
- Exchange full financial disclosure. Each partner sets out assets, property, savings, pensions, business interests, income and debts in a full and frank disclosure.
- Agree fair terms. Decide how separate and joint property are treated and how you would provide for each other – see what to include and how to keep it fair.
- Take independent legal advice. Each partner should have their own advice on what they are signing.
- Sign it as a deed. Each partner signs in front of an independent witness, and the agreement is executed as a deed.
Our full walk-through in how to get a postnup covers each stage in detail.
The calm-timing advantage
There is one respect in which making a postnup years into a marriage can actually be an advantage. A prenup is sometimes challenged on the basis that it was signed under the pressure of an approaching wedding – that a partner felt they had no real choice with the date looming (see duress and prenups). A postnup made calmly, with no wedding deadline in sight, is far harder to portray that way. The absence of time pressure makes it easier to show the agreement was freely entered into, which is one of the very things a court looks for.
The usual limits still apply
A postnup made after years of marriage is subject to exactly the same limits as any nuptial agreement. It is not automatically binding, and a court retains its discretion under the Matrimonial Causes Act 1973. Two backstops always remain: an agreement cannot leave a partner in real financial need, and it cannot pre-determine arrangements or maintenance for children, whose welfare comes first. Within those limits, though, a fair agreement made with disclosure and advice is given significant weight – the same principles from Radmacher v Granatino that apply to prenups apply here, as we explain in are postnups legally binding?
A worked example: a business built during the marriage
Imagine a couple who married in their twenties with very little between them. Fifteen years later, one partner has built a successful company that employs a dozen people, while the other stepped back from paid work to raise their children and run the household. Neither of those things was true on the wedding day, so nothing the couple might have agreed back then would fit their lives now. A postnup lets them address the business directly: they might agree that the company itself stays with the partner who runs it, while the value built up during the marriage is shared in a defined way, and the home plus a fair level of maintenance protect the partner who gave up earnings to support the family. That is a far clearer and fairer outcome than leaving everything to be argued over years down the line – and it is exactly the kind of situation a postnup is built for. See protecting a family business for more on how this is done.
How a long marriage changes the picture
One thing to be realistic about is that the longer you have been married, the more your finances tend to have merged, and the harder it becomes to treat everything as strictly separate. A court looks at the whole picture, including how long the marriage has lasted and the contributions each partner has made – financial and non-financial. In a long marriage the distinction between matrimonial and non-matrimonial property can blur, and assets that started out as one partner's can become shared through years of joint use. A postnup made later in a marriage should reflect that reality rather than pretend it away: the most robust agreements ring-fence genuinely separate assets – an inheritance kept apart, say – while accepting that jointly built wealth will usually be shared. Terms that try to strip a long-married partner of any share of what the couple built together are the ones most likely to be judged unfair.
What to watch for when making one later on
A few practical points matter more the longer you have been married. First, gather genuinely up-to-date figures – pensions in particular can have grown far beyond what either partner assumes, so obtain current valuations rather than guessing (our guide to valuing assets helps). Second, be honest about joint contributions: an agreement that ignores years of unpaid work raising children or running a home will look unfair. Third, keep the tone collaborative. Raising a postnup after fifteen contented years can feel loaded, so frame it as sensible housekeeping you are doing together – our guide to how to talk about an agreement applies just as well after the wedding as before it.
Getting a postnup after marriage: is it ever too late?
It is never too late to get a postnup after marriage. Couples make one a year in or twenty years in, usually because something has changed – an inheritance, a new business, a property purchase, or simply a wish for the clarity they never put in place before the wedding. The later timing can even help: with no wedding deadline, it is easier to show the agreement was made calmly and freely. Provided you both disclose fully, take independent advice and agree fair terms, an agreement signed decades into a marriage carries the same weight as one signed on the eve of the wedding – and often more.
Postnup after marriage: FAQs
Can you get a postnup 10 or 20 years into a marriage?
Yes – there is no time limit. You can make a postnuptial agreement at any stage of a marriage, and many couples do so decades in when their finances have changed.
Is a postnup made years later still valid?
It is treated like any nuptial agreement – given significant weight if it is fair, made with full disclosure and backed by independent advice (see are postnups binding?).
Is a postnup the same as a prenup after marriage?
Effectively, yes. People sometimes ask for a "prenup after marriage", but the correct term is a postnup – the same document, signed after the wedding (see prenup vs postnup).
Why would a long-married couple want a postnup?
Usually because circumstances have shifted – an inheritance, a business, a property purchase or a wish to protect assets for children. A postnup brings the financial arrangements up to date.
Does a postnup after years of marriage need a solicitor?
Not to be valid, but independent legal advice for each partner is strongly recommended and helps the agreement hold up (see do you need a solicitor?).
How much does a postnup cost later in a marriage?
The same as at any other time – from £199 online to four figures with a solicitor (see how much a postnup costs).
Can a postnup protect a business started during the marriage?
It can set out how the business is treated, though a company built up during the marriage is usually shared to some degree. A postnup can define how its value is divided (see protecting a business).
Do we need to disclose finances again if we married long ago?
Yes – fresh full disclosure is what keeps a late postnup fair, especially as pensions and property may have grown considerably since the wedding.
Create your prenuptial agreement online
UK Prenup lets couples in England & Wales create a clear, fair prenuptial agreement online from £199, with your document generated instantly as a PDF. See how it works or get started.
UK Prenup is not a law firm and does not provide legal advice. A prenuptial agreement in England & Wales is not automatically binding, and both partners should take independent legal advice before signing.