It is one of the most common requests we receive from couples drafting an antenuptial contract: "Can we include a clause that punishes the spouse who cheats?" The desire is understandable. No one enters a marriage expecting infidelity, but couples want the reassurance that if it happens, the innocent party will be financially protected. The short answer is that South African law offers some limited scope for deterrence clauses, but punitive forfeiture clauses triggered by infidelity are fraught with legal risk and practical difficulty. In most cases, couples are better served by the existing statutory protections than by attempting to draft a contractual remedy. This article explains the legal position, the practical problems, and the available alternatives.
South African law grants couples wide freedom to include provisions in their antenuptial contract. The Matrimonial Property Act does not prescribe a fixed set of clauses — parties are generally free to regulate their matrimonial property regime as they see fit. However, this freedom has limits. A clause in an antenuptial contract may not be:
Any clause that falls foul of these principles is null and void. This is where infidelity clauses run into difficulty.
The typical request looks something like this:
In other words, the cheating spouse gets nothing, and the innocent spouse gets everything — or at least more than they would ordinarily receive. While the emotional logic is clear, the legal reality is more complicated.
Section 9(1) of the Divorce Act 70 of 1979 already provides a statutory mechanism for forfeiture of patrimonial benefits. A court may order forfeiture — in whole or in part — if it is satisfied that:
This is a judicial discretion exercised by a court considering all the facts. An antenuptial clause that attempts to predetermine the outcome of this assessment — by automatically stripping one spouse of their accrual claim based on a single contractual trigger — arguably purports to take over a function that the law reserves for the court. South African courts have consistently held that a clause in an ANC that removes a spouse's right to seek forfeiture or share in the accrual is unenforceable. The reverse — a clause that automatically imposes forfeiture — faces the same objection from the opposite direction: it seeks to do what only a court should do.
What constitutes "infidelity" for the purposes of triggering a contractual penalty? A physical sexual affair is the obvious case, but the boundaries are far from clear:
These questions are not hypothetical — they are the exact disputes that arise when parties attempt to enforce vague contractual provisions. Without a clear, agreed definition and a mechanism for adjudication, the clause creates more litigation than it prevents.
In a contractual forfeiture scenario, the innocent spouse would need to prove the infidelity to the court's satisfaction. This typically means:
Infidelity is notoriously difficult and expensive to prove in court. The process is adversarial, intrusive, and emotionally devastating — precisely the opposite of what most couples hope for when they include the clause.
A clause that imposes a disproportionate financial consequence for a breach of a marital obligation may be treated as a penalty clause under the Conventional Penalties Act 15 of 1962. A court may reduce the penalty to an amount it considers fair in the circumstances. This means the clause may not deliver the outcome the parties intended, even if it is technically enforceable.
South African case law does recognise a narrow exception. Where a couple has a specific history of infidelity — for example, they divorced previously because of one spouse's extramarital affairs and are now remarrying — a clause designed to deter a repeat of that specific conduct may be enforceable. The reasoning is that such a clause seeks to preserve the marriage rather than to punish. The context matters: the clause must be reasonable, proportionate, and directed at a genuine and identified risk. An example of potentially enforceable wording:
"Should it be proven that Spouse A caused the dissolution of the marriage through an extramarital relationship, Spouse A shall [specific, proportionate obligation — e.g., transfer a specified property to Spouse B / pay a specified sum to Spouse B]."
Even here, enforceability is not guaranteed. The clause must survive scrutiny for reasonableness, public policy, and proportionality. A court retains the discretion to decline enforcement if the outcome would be unjust.
For most couples, the existing statutory framework provides a more reliable — and more flexible — remedy than a contractual infidelity clause. Section 9(1) of the Divorce Act allows a court to order the forfeiture of patrimonial benefits if it finds that one spouse would be unduly benefited and that the circumstances, including misconduct, justify the order. Importantly, the court considers the totality of the circumstances, not just a single event. This includes:
Recent case law confirms that adultery alone is generally not sufficient to justify a forfeiture order. The misconduct must be "substantial" and must have materially contributed to the breakdown of the marriage. In M.C.M v M.S.M [2025] ZALMPPHC 153, the Limpopo High Court emphasised that mere infidelity without additional aggravating factors — such as financial misconduct, deception, or calculated exploitation — typically does not meet the threshold for forfeiture. This may seem like a weaker remedy than an automatic contractual trigger, but in practice, it is more robust. A section 9 order is made by a court with full knowledge of the facts, is enforceable as a court order, and is less susceptible to challenge than a contractual clause.
The Constitutional Court's landmark judgment in EB (born S) v ER (born B) and Others [2023] ZACC 32 has further expanded the remedies available to a disadvantaged spouse. Following this judgment, even a spouse married under an ANC that excludes the accrual system can now apply to a court for a redistribution order under section 7(3) of the Divorce Act if the outcome would otherwise be unjust. This means the protective net for an innocent spouse is wider than ever. The law is moving towards ensuring fair outcomes based on all the circumstances — not on rigid contractual triggers.
We advise most couples against including infidelity forfeiture clauses in their antenuptial contracts. The reasons are practical and legal:
If a couple has a specific and documented history of infidelity (for example, a remarriage after a prior divorce caused by adultery), a carefully drafted deterrence clause with proportionate consequences may be considered. Even then, it should be drafted conservatively and with clear advice about its limitations.For all other couples, our recommendation is to rely on the existing statutory protections, which are designed to balance fairness, judicial oversight, and the realities of marriage breakdown.
At Louwrens Koen Attorneys, we have extensive experience drafting antenuptial contracts tailored to the specific needs and circumstances of each couple. We will advise you honestly about what is enforceable and what is not, and ensure your contract provides meaningful protection within the bounds of the law. If you have questions about infidelity clauses, forfeiture of benefits, or any other aspect of your antenuptial contract.
Louwrens Koen Attorneys
Disclaimer: This article is intended for general information purposes and does not constitute legal advice. The enforceability of specific clauses depends on the circumstances of each case. Consult an attorney before including non-standard provisions in an antenuptial contract.
