Montana Divorce Law And Proving Infidelity: What You Need To Know

Divorce can be a challenging and emotional process, especially if you suspect that your spouse has been unfaithful. In the state of Montana, there are specific laws and procedures that dictate how divorce is handled, including how judges determine if infidelity has occurred. If you are considering divorce and believe that your spouse has been unfaithful, here is what you need to know about Montana divorce law and proving infidelity.

Grounds for Divorce in Montana

To obtain a divorce in Montana, you must have valid legal grounds for ending your marriage. Unlike some states, Montana is a "no-fault" divorce state, meaning that neither spouse has to prove wrongdoing by the other spouse to obtain a divorce. Instead, either spouse can file for divorce based on the grounds that the marriage has irretrievably broken down.

Proving Infidelity in Montana

Although proving infidelity is not necessary to obtain a divorce in Montana, it can still be a relevant factor in a judge’s decision regarding alimony, property division, and child custody. If infidelity was a factor in the breakdown of the marriage, it may be considered when determining spousal support, especially if the unfaithful spouse spent marital assets on extramarital affairs.

However, proving infidelity can be challenging, and there is no single way to do it. Montana divorce law requires that evidence of infidelity must be "clear, unequivocal, and convincing." This means that mere suspicion or innuendo is not enough to prove infidelity; you must have clear and convincing evidence to back up your claims.

Types of Evidence of Infidelity

There are several types of evidence that may be used to prove infidelity in a Montana divorce case. Some of the most common types of evidence include:

1. Surveillance Evidence

Surveillance evidence, such as photographs, videos, or audio recordings, can be compelling evidence of infidelity. Private investigators may be hired to collect this type of evidence, but it can also be gathered by spouses if they believe that their spouse is engaging in an extramarital affair.

2. Witness Testimony

Witness testimony from individuals who have firsthand knowledge of the infidelity can also be a useful way to prove unfaithfulness. This might include a friend of the unfaithful spouse who witnessed their behavior or text messages from a romantic partner.

3. Financial Records

Financial records, such as bank statements, credit card statements, or receipts, can provide evidence of infidelity, especially if they demonstrate that a significant amount of marital assets were spent on extramarital affairs.

Adultery and Montana Divorce Law

Adultery is not a criminal offense in Montana, nor is it explicitly defined in the state’s divorce laws. However, Montana courts have recognized adultery as a ground for divorce on several occasions.

If a spouse believes that their partner has committed adultery, they must prove it to the court by providing clear, unequivocal, and convincing evidence. If adultery is proven, it might impact spousal support, child custody, and property division, depending on the circumstances.


Proving infidelity in a Montana divorce case can be difficult, but it can impact important decisions, such as spousal support, child custody, and property division. If you believe that your spouse has been unfaithful, it is important to gather evidence and seek the advice of a skilled divorce attorney. An experienced attorney can help you navigate the complex divorce process and ensure that your rights are protected.

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