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1 October 2025

Infidelity In Your Marriage: Understanding Your Legal Options (29 September 2025)

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Duncan Lewis & Co Solicitors

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Duncan Lewis Solicitors is an award-winning and Times 200 ranked law firm offering expert services in 25 fields, including family law, business immigration, high net divorce, personal injury, commercial litigation, property law, motoring, education and employment.
Discovering infidelity in your marriage strikes at the core value of a marriage… trust.
United Kingdom Family and Matrimonial
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Discovering infidelity in your marriage strikes at the core value of a marriage... trust. It can leave you feeling betrayed and emotionally wounded, whether you have discovered your spouse had a one-night stand or was involved in a long-term affair. It may feel like a deep personal violation, which can cause feelings of anger, confusion and self-doubt, likely leaving you asking yourself the question of 'what should I do next'?

Aside from trying to unpack the impact of this on you and getting support with the emotional side of this, you may too start thinking about the legal implications. 'Has this marriage come to an end?' 'Is it salvageable?' 'What can I do to strategically plan in the interim?'

This is an incredibly personal and difficult decision to make which time, support and often legal and professional guidance can help through the process.

Duncan Lewis private family law solicitor Isabella Gill looks at this sensitive issues and sets out the options below

Is your marriage over or could you reconcile?

Before commencing any legal proceedings, you must be able to tell the court that you feel your marriage is beyond repair. Before determining your next step therefore, you must consider whether your marriage has come to an end. There is no rulebook on deciding whether your marriage is really over and this is a question only you can answer. If your partner has come clean with you, you may find you have a starting block for constructive conversations about your relationship, however, if you discovered the infidelity this could likely exacerbates the emotions of deceit and leave you feeling the marriage has reach the end. If you are struggling with the emotional turmoil of discovering infidelity it is important to reach out to your support network or a counsellor who can assist with navigating this issue.

Legal implication of infidelity on divorce

There remains only one ground for divorce in the UK... that is the irretrievable breakdown of the marriage. Once you feel sure, the next steps are considering when and how to proceed with commencing divorce proceedings.

Since the introduction of the no-fault divorce in 2022, there is no legal requirement to assign fault in a divorce. Prior to this, a spouse was required to make accusations about the other's conduct, such as adultery, regardless of whether there has been a mutual decision to separate. Since 2022 the only basis for divorce is to tell the court that the marriage is beyond repair. Once divorce is commenced (which you can do alone as a 'sole applicant', or together with your spouse as 'joint applicants'), you will need to deal with separating the finances and make arrangements for the children (if you have any).

Whilst infidelity is very destructive to a marriage and the life you have with your spouse, by itself it does not typically impact the outcome of your divorce financial settlement in the UK. It is unlikely that the court would deem it relevant when considering each parties' case. It could however become relevant if you have discovered your partner has caused you financial hardship as a result of the infidelity e.g. evidence demonstrating your partner recklessly used joint assets to fund an affair, although this is hard to prove.

The court's primary focus is on meeting the needs of the children and indeed both spouses, and thereafter ensuring a fair division of the assets.There is no 'one size fits all' solution for cases, contrary to popular belief.

Legal implications of Infidelity on the arrangements for the children

Where there are children involved, the court's paramount consideration is the welfare of the children. When making any final determination about the arrangements for the children following their parent's separation, the court considers the welfare checklist set out at Section 1 of Children Act 1989. The checklist includes consideration for the child's wishes and feelings, the child's physical, emotional and educational needs, the likely effect on the child of any change in circumstances, the child's age, sex, background, any relevant characteristics and any harm the child has suffered or is at risk of suffering.

Again, the infidelity itself may not impact your spouse's right to see their children. The court could, however, conduct investigative work with the children to consider whether the children's wellbeing may be directly impacted by the infidelity, for instance if your partner has decided to pursue a new relationship and that new person poses a risk to the children. Should evidence or expert opinion confirm the children could be at risk of harm this will be considered by the court when making determination for the child arrangements, i.e. where they live and who they spend time with.

When to speak to a solicitor or legal advisor?

Whether you have decided your marriage is over or you're still unsure, it can really help to speak to a lawyer early on. If you feel your marriage has come to an end, remember that divorce is not a failure — it can be a brave step towards a fresh start and a happier future. Getting early legal advice means you will understand your rights and choices from the outset, which can make everything feel a little less overwhelming.

If you are hoping to rebuild your relationship, you might want to explore whether a post-nuptial agreement would be appropriate. This can give both of you clarity and reassurance about how things would be handled if you were to separate later on.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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