Adultery Laws in Massachusetts (2026): Still Illegal or Ancient History?

Most people assume adultery is either a serious crime or totally irrelevant to the law. In Massachusetts, the truth is somewhere in the middle. And honestly, it’s more complicated than you’d think.

Here’s what you need to know about adultery laws in Massachusetts in 2026 and how they could affect you.

What Is Adultery?

Adultery means having sexual relations with someone who is not your spouse. In legal terms, it specifically refers to a married person engaging in sex outside of the marriage.

You might hear the words “adultery” and “infidelity” used the same way. They are similar, but not the same. Adultery is a legal term. Infidelity is a broader word. Infidelity can include emotional cheating. Adultery, legally speaking, means sexual activity outside of marriage.

Pretty straightforward, right?

Is Adultery Still a Crime in Massachusetts?

Here’s where it gets interesting. Hold on, because this surprises most people.

Adultery used to be a crime in Massachusetts. For a long time, it was actually a felony. The old law, found in Massachusetts General Laws Chapter 272, Section 14, said that anyone who had sex outside of their marriage was guilty of adultery. The penalty was steep. You could face up to three years in state prison, up to two years in a county jail, or a fine of up to $500.

But in July 2018, Massachusetts repealed that law. Gone. It is not a crime anymore to have an affair in Massachusetts.

The last time Massachusetts actually prosecuted someone for adultery was nearly 40 years before the repeal. The defendants in that case were fined just $50. So the law had basically stopped being enforced long before it was officially removed.

Wait, Is Any Part of Adultery Still Illegal?

Okay, pause. Read this carefully.

There is one surprising exception that still exists on the books. Massachusetts General Laws Chapter 208, Section 40 says that two people who were divorced from each other but are living together again as a couple can still be considered guilty of adultery.

That’s right. If you divorce your spouse and then move back in together as a couple, that can technically be treated as adultery under Massachusetts law. This old law is still on the books, though it is rarely enforced and has been discussed as a candidate for repeal.

Most people have no idea this rule exists. You’re not alone in that.

Adultery and Divorce in Massachusetts

Just because adultery is no longer a crime doesn’t mean it has no legal consequences. It can absolutely affect your divorce case. Here’s how.

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Fault-Based vs. No-Fault Divorce

Massachusetts allows two types of divorce. You can file a no-fault divorce, which says the marriage has broken down with no chance of repair. Or you can file a fault-based divorce, where you blame the other spouse for causing the marriage to fail.

Adultery is one of the recognized reasons for a fault-based divorce in Massachusetts. If your spouse cheated, you can use that as the official reason for the split.

But here’s the thing. Many lawyers actually advise against it.

Filing a fault-based divorce based on adultery requires you to prove the affair happened. That means gathering evidence. It can drag out the process, cost more money, and make everything more public. Fault-based divorces often become part of the court record, which anyone can look up.

A no-fault divorce skips all of that. You don’t need to prove anything. The marriage is simply over. For most people, that is the faster and cheaper option.

One Big Advantage to Citing Adultery

There is one real perk to filing on adultery grounds. You don’t have to wait. In a no-fault divorce, Massachusetts requires you to wait at least six months before the case is heard. But if you file on fault grounds like adultery, there is no waiting period. Your case can move forward much faster.

So if speed matters to you, a fault-based divorce could actually save time and legal fees even if it costs more energy upfront.

How Adultery Affects Property Division

Now, here’s where things get serious.

Massachusetts uses something called “equitable distribution” when dividing property in a divorce. That means a judge divides assets in a way that is fair, but not necessarily 50/50.

Adultery itself usually does not change how property is divided. Courts focus on financial fairness, not punishing bad behavior. But there is one important exception.

If your spouse spent marital money on the affair, that can matter a lot. Think expensive hotel stays, lavish gifts for a lover, travel, and other costs. That spending reduced the total amount of money and assets available for both of you. A judge can account for that. The innocent spouse may receive a larger share of the remaining assets to make things fair.

So if you suspect your spouse drained shared funds during an affair, gather your bank statements and credit card records. That evidence could be very valuable.

How Adultery Affects Alimony

A lot of people going through divorce assume the cheating spouse will be forced to pay more alimony. Often, that’s not how it works.

In 2011, Massachusetts passed the Alimony Reform Act. That law specifically removed “fault” and conduct from the list of factors a judge considers when deciding alimony. Courts today focus mainly on financial need. How long were you married? What are each person’s earning abilities? What is the lifestyle you both shared?

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Adultery is basically not a factor in deciding alimony amounts. A judge won’t dramatically increase payments just because someone cheated.

There is a small exception. If the cheating spouse spent so much money on the affair that it reduced the couple’s shared finances, a judge might consider that when deciding whether to give the innocent spouse more in property division or support. But that’s tied to the financial damage, not the cheating itself.

How Adultery Affects Child Custody

This one matters most to parents. So let’s break it down clearly.

In Massachusetts, both parents have equal rights to custody unless there is evidence of serious misconduct. Adultery by itself is not that kind of misconduct. Courts care about one thing above everything else: what is best for the child.

If the affair had no impact on the children, then it basically won’t affect custody decisions.

But if the affair did harm the children, that changes things. For example, did the cheating parent leave a young child home alone to spend time with their lover? Did the affair expose the child to dangerous situations or an abusive person? In those cases, the adultery becomes relevant because it affected the child’s well-being.

Child support works the same way. Adultery doesn’t directly affect how much support is paid. That amount is calculated based on each parent’s income, time spent with the children, and related costs.

Proving Adultery in Court

Sound complicated? It is a little. Let me walk you through it.

If you want to use adultery as grounds for your divorce, you have to prove it actually happened. Massachusetts requires what’s called “clear and convincing evidence.” That is a higher standard than just suspicion or rumor.

What counts as evidence? Things like text messages or emails between the spouses, testimony from a neutral third party who witnessed something, or even circumstantial evidence can be used. For example, a witness who saw your spouse entering someone’s home late at night and not leaving until morning might be enough.

Vague suspicion is not enough. Just because your spouse spent a lot of time with someone else doesn’t prove adultery on its own.

One important change came with the 2018 repeal. Before adultery was decriminalized, a spouse could refuse to answer questions about an affair in court by invoking their Fifth Amendment right against self-incrimination. That right only applies to criminal matters. Now that adultery is no longer a crime, that protection is gone. Spouses can now be required to answer questions about cheating in family court proceedings.

Should You Hire a Lawyer?

Honestly, yes. Especially if adultery is involved in your divorce.

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Every case is different. The impact of an affair on your divorce depends on your specific situation. A skilled family law attorney can help you figure out whether to file a fault or no-fault divorce, how to gather and present evidence, and how to protect your rights when it comes to money, property, and kids.

Going it alone in a contested divorce involving adultery is really risky. A lawyer can help you avoid costly mistakes.

Frequently Asked Questions

Is adultery a crime in Massachusetts in 2026? No. Massachusetts repealed its criminal adultery law in 2018. Cheating on your spouse is no longer a criminal offense in this state.

Can I get divorced because my spouse cheated? Yes. Adultery is still a recognized legal ground for a fault-based divorce in Massachusetts. You will need to prove it happened.

Does adultery affect alimony payments? Usually not directly. Massachusetts law does not list fault or conduct as a factor in alimony decisions. However, if the affair involved spending shared marital money, that could influence property division.

Will cheating affect child custody? Generally no, unless the affair directly harmed the children or affected the parent’s ability to care for them. Courts focus on the child’s best interests.

Is there any form of adultery that’s still technically illegal? Yes. Under Massachusetts law, divorced couples who move back in together and live as a couple can still technically be considered guilty of adultery. This old law is still on the books.

Does it help to file on adultery grounds instead of no-fault? Sometimes. The main advantage is skipping the six-month waiting period. The disadvantage is that you must prove the affair, which takes time, money, and effort.

What kind of proof do I need to show adultery happened? Massachusetts courts require “clear and convincing” evidence. This can include messages, testimony from witnesses, or strong circumstantial evidence like someone being seen entering and leaving a lover’s home.

Final Thoughts

Massachusetts has come a long way on adultery laws. It’s no longer a crime. But it can still matter a lot when a marriage ends.

If your spouse cheated and you’re thinking about divorce, your best move is to talk to a family law attorney. They can help you figure out the smartest path forward based on your specific situation.

Now you know the basics. Stay informed, protect yourself, and don’t make major legal decisions without getting proper advice first.