Who should have an anti-adultery clause in their prenuptial agreement?

justprenups.com • January 12, 2026

Even if you’re not the one who cheated, the wrong anti-adultery clause can work against you.

An anti-adultery clause? In one of our legal products? You won’t find an anti-adultery clause in the majority of our prenuptial agreements and postnuptial agreements. As an experienced divorce attorney,  Chantale knows that anti-adultery clauses lead to complicated and expensive litigation that is often just as painful as the infidelity. They lengthen divorce proceedings and seldom provide the hurt, faithful partner with closure.

 

JustPrenups offers only one anti-adultery clause, a version that is acceptable because it does not introduce burdensome requirements for defining “adultery” and for proving that adultery occurred. It’s still not for everyone. If a couple cannot have children or is past the age of having children, then they do not need our anti-adultery clause.

 

But if either of you can have children (i.e., you’re in your childbearing years and capable of having children), then yes, you may need our singularly acceptable anti-adultery clause.

 

Why does JustPrenups dislike most anti-adultery clauses? Because they’re expensive and undermine all our hard work to create a prenup that keeps you OUT of court.

 

Being cheated on is a painful, biting betrayal. But anti-adultery clauses are contrary to one of the primary reasons for a prenup: to save you money on attorney fees and reduce the overall cost of divorce litigation. If you try to enforce an anti-adultery clause in divorce court, you’ll open the door to an expensive dispute. The adultery issues must be mediated or, most likely, handled by a judge. That means open your wallet. Some of the most expensive professionals will now be on your personal divorce payroll.

 

And what about all the measures you took to create the prenup to bypass attorneys, judges, and the family law system? You have now invited all those people and issues back into your life through your prenup via the anti-adultery clause. There will be court fees and time missed from work. Mediators will have their own price tags. The total fee for your attorney will depend on the number of hours required, which isn’t necessarily predictable or guaranteed, and is often driven by your spouse’s attorney, who will not be above making the fight as expensive for you as possible.

 

Why does JustPrenups dislike most anti-adultery clauses? Because even if you can afford the fight, your anti-adultery clause may still be ineffective…or backfire.

 

Even if you’re not the one who cheated, an anti-adultery clause can work against you.

 

You might think that, as the betrayed spouse, there will be a predictable outcome in court, that the judge will sympathize and be hostile to your soon-to-be ex. But we don’t know the life experiences of the judge or mediator. They may have strong feelings about adultery. Maybe the judge is an adulterer or was wrongly accused of cheating. You cannot assume that everyone involved in the divorce court process will empathize with you and feel the same about the “karma” that you want to happen. This disappointment can compound the pain of a spouse’s infidelity.

 

How will you define adultery in court?

 

Adultery is analytically problematic. It’s hard to define, even though the meaning may seem obvious. Is your spouse cheating if they regularly send naughty messages to a paid model through an online platform? Is physical affection without sex still cheating? Are these enough to trigger the anti-adultery clause in your prenup? And don’t forget that the judge may have a very different definition from yours.

 

Let’s consider another scenario. Your husband was emotionally but not physically intimate with a mistress, diverting his emotional energy, quality time, and effort from the marriage. Your judge may not consider an emotional affair as adultery, even though you paid the price of becoming alienated from your husband because of his relationship choices outside the marriage.

 

To some, an emotional affair is the most painful kind of adultery because emotional attachment to another person is tough to overcome. But another person might see their wife’s one-night affair during a business trip as worse because it was only sexual. Someone else might consider texting, emailing, and calling an ex-girlfriend or ex-boyfriend every week for a year an even uglier form of adultery, one more likely to erode a marital bond, even though they never met in person.

 

All of these scenarios hurt the faithful partner. While a judge may acknowledge the faithful partner’s pain, the judge may also believe that enforcing a basic anti-adultery clause is not merited. While your spouse may, in fact, be a cheater, and while their behavior may be wholly unjustifiable, your litigation results may not reflect what is self-evident in your experience. 

 

How will you prove adultery in court?

 

Let’s assume you’ve already cleared the first hurdle: defining “adultery.” The next question is the real problem—what actually counts as convincing proof of adultery in court?

 

Hotel receipts? Jewelry? Flowers?

 

If you’ve seen Heartburn—based on Nora Ephron’s novel—you know Meryl Streep’s character found those items pretty persuasive. And emotionally, she was absolutely right. Legally? Not so much.

 

In a courtroom, a flower receipt doesn’t prove anything. Neither does a hotel bill. Even jewelry, standing alone, won’t cut it. Such receipts are insufficient to trigger or enforce a punitive prenuptial provision.

 

Movies usually gloss over this part, but litigation is allergic to assumptions. The other side always gets a say, and alternative explanations matter. Business trips generate hotel receipts. Social outings can, too—especially if alcohol is involved. People buy flowers and jewelry for relatives, coworkers, friends, or themselves. A receipt shows a purchase, not infidelity. Quite often, all you really have is that uneasy gut feeling that something’s off.

 

So, what about suggestive texts? Flirty messages? Provocative photos?

 

Same problem. Texts and images, by themselves, usually don’t prove adultery. What looks racy or inappropriate to you may strike a judge as banal, ambiguous, or irrelevant. This is deeply subjective, and your judge doesn’t live inside your marriage.

 

And that’s the hardest part. As a spouse, you know your partner’s baseline. You know what’s normal for them—their habits, tone, grooming, schedule, energy, even their smell. You notice the small deviations immediately. But your judge doesn’t have that history or context. A photo that screams “this is not normal” to you may look entirely unremarkable to someone seeing it for the first time. Your lived intuition, however accurate, isn’t evidence.

 

Bottom line: receipts, vibes, behavioral changes, and suspicions aren’t enough to enforce even a basic anti-adultery clause in a prenup.

 

If you want proof that actually moves the needle, you usually need more—and that almost always means hiring a private investigator. That’s never been cheap, and inflation hasn’t helped. You don’t know how many hours it will take, whether anything conclusive will be found, or whether the evidence will ultimately be persuasive.

And here’s the irony: once you’re paying a private investigator, you’ve added yet another expensive professional to your divorce tab—undercutting one of the main reasons people sign prenups in the first place. Saving time and money.

 

If You Take the Time and Pay the Costs of Proving Adultery, Will You Get Paid?

 

Maybe not. Most anti-adultery clauses give an alimony-based consequence for infidelity. A person might be required to pay more alimony, or receive less, if they were the adulterer. The problem with that framework is enforceability. If the court determines a person has no ability to pay alimony, the court will not enforce any obligation that is beyond an ability to pay, even if related to adultery and required under a prenup. You will have spent months or years paying for lawyers, a private investigator, and possibly a forensic computer expert. You proved the adultery. But you still won’t get paid, and the adulterer still isn’t “punished.”

 

Is there no Anti-Adultery Clause that JustPrenups Likes?

 

From JustPrenups' perspective, there is one exception to our general opposition to anti-adultery clauses. It requires specific circumstances and meticulous drafting. We call it our SAFE clause, which stands for Secure Adultery Finances Exception clause.

 

Want to learn about the SAFE clause and how we draft it? See our post, The SAFE Clause: The Only Worthwhile Anti-Adultery Clause.


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By justprenups.com January 12, 2026
SAFE stands for Secure Adultery Finances Exception, and there’s a reason we built it this way. If you’ve already read our prior post on why most anti-adultery clauses fail, you know the problem: defining adultery is messy, proving it is harder, and enforcing it often costs more than it’s worth. The SAFE clause exists to work around those realities rather than fight them. Should You Include a SAFE Clause? As a general rule, most couples should avoid anti-adultery clauses altogether. They tend to add time, expense, and uncertainty to divorce proceedings—the exact opposite of what a prenup is supposed to do. Even when one spouse knows the truth, proving adultery in court is another matter entirely. That said, some couples are insistent. They know they’ll feel more secure with some form of protection in place. If that’s you, there’s one threshold question you need to answer first: Are you a couple of child-bearing age and capable of having children? If the answer is no, the SAFE clause won’t add meaningful value to your prenup. But if the answer is yes, this clause may be a good fit—if you understand how it works and why it’s structured the way it is. What the SAFE Clause Actually Does The SAFE clause is not about policing adult behavior. It’s about protecting children and preserving family resources. Specifically, it addresses children born outside the marriage and the financial impact that can have on children of the marriage. At its core, the clause says something like this: If, during the marriage, one spouse has a child with someone other than their spouse within ten (10) months of either party filing for divorce, that child is presumed to be the result of an adulterous relationship. As a result, the unfaithful spouse will receive only ___% of the marital assets and/or assume ___% of the marital liabilities. The ten-month window can be adjusted. The asset split can be adjusted. The mechanics are flexible. The point is simple: if adultery produces a child, the financial consequences shift. Why This Isn’t “Punitive” At first glance, this may feel punitive. But the goal isn’t punishment, it’s resource preservation. There is a finite pool of marital assets. Those assets fund alimony, support children of the marriage, and—under the law—must also support children born outside the marriage. When a third child enters the picture, those resources get stretched thinner. And the people who usually pay the price are the children of the marriage. Let’s start with a baseline scenario to illustrate: 1. Arthur and Betty are married and have one daughter, Cheryl. 2. Together, they build substantial assets through careful investing and saving. 3. They divorced simply because they grew apart. There was no adultery. 4. Arthur receives 50% of the marital assets through the divorce. 5. Betty receives 50% of the marital assets through the divorce. 6. When Arthur dies, Cheryl inherits Arthur’s 50%. 7. When Betty dies, Cheryl inherits Betty’s 50%. Result: everything Arthur and Betty built together ultimately goes to Cheryl, precisely as intended. Now, Add a Child Born Outside the Marriage Let’s introduce two legal facts: • A child born outside the marriage is entitled to child support. • That child has inheritance rights. With that in mind: 1. Arthur and Betty are married and have one daughter, Cheryl. 2. They build significant marital assets together. 3. Betty has an affair with another man. 4. Betty has a child, Delilah, with the other man. 5. Arthur and Betty divorce. 6. Arthur gets 50% of the marital assets through the divorce. 7. Betty gets 50% of the marital assets through the divorce. 8. Betty must use part of her share to support Delilah. 9. When Arthur dies, Cheryl inherits Arthur’s assets. 10. When Betty dies, Cheryl and Delilah split Betty’s assets equally. Result: The economic hit lands hardest on Cheryl. Arthur had no say in the affair. Cheryl had no say in the affair. Yet the assets Arthur and Betty built together—intended for Cheryl—are permanently reduced to support a child born outside the marriage. Delilah isn’t at fault either. She can’t be disinherited or punished for circumstances she didn’t choose. But that doesn’t change the financial reality. How the SAFE Clause Fixes This A properly drafted SAFE clause changes the divorce math before that damage occurs. In this scenario, the clause might provide that Arthur—the non-cheating spouse—receives 75% of the marital assets. That allows Cheryl’s expected inheritance to remain intact through Arthur, while still ensuring Delilah receives the support and inheritance the law requires. No prenup can fix the emotional fallout of adultery, especially when it creates a half-sibling. But a prenup can prevent avoidable financial harm to the children of the marriage. Why a SAFE Clause is Worthwhile When Other Clauses Are Not The SAFE clause sidesteps the three biggest problems with traditional anti-adultery provisions: • Definition: No debates about what counts as cheating. • Proof: No reliance on receipts, texts, or subjective interpretations. • Ability to Pay: No court determination of ability to pay alimony because the SAFE clause is marital asset-based, not alimony-based. A child conceived and born outside the marriage is an objective, legally recognized fact. That makes the clause far easier and less costly to enforce than any behavior-based alternative. In addition, the SAFE clause triggers a change in the division of marital assets, not an alimony recalculation. So, there is no judicial “ability to pay” analysis that makes many alimony-based anti-adultery clauses unenforceable or uncollectible. That said, drafting a comprehensive SAFE clause correctly is very technical, and pitfalls must be avoided. It needs to be done carefully to be enforceable and fair—but when done right, it’s the rare anti-adultery clause that can actually deliver while remaining consistent with what couples want from a prenup.
By Cindy Aldridge December 31, 2025
Newlyweds face a joyful—and sometimes awkward—shift: two financial histories become one shared future. Whether you’re merging accounts or just calendars, the first year of marriage is the best moment to align money habits, expectations, and goals so finances support your relationship instead of stressing it.
By Cindy Aldridge December 18, 2025
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