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,  JustPrenups 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.