How Adultery Impacts Divorce and Custody in Family Law Cases

Adultery is one of the more emotionally charged issues in divorce. It not only contributes to the breakdown of trust between spouses but can also affect how legal matters are handled during separation. In family law, infidelity may influence decisions around asset division, spousal support, and in some cases, child custody.

In 2020, Canada’s divorce rate dropped to 5.6 per 1,000 married individuals—the lowest it’s been since 1973. Although fewer people are choosing to marry, this decline in divorce doesn’t necessarily indicate that more couples are staying together. Instead, it reflects a complex mix of social, economic, and cultural shifts.

However, infidelity is a common factor in the breakdown of marriages worldwide, often leading to divorce as trust between partners is deeply compromised.

This article examines how adultery is treated in family law, with a focus on its potential impact on divorce proceedings, financial arrangements, and custody decisions.

Adultery and Grounds for Divorce

Adultery is often cited as a key factor in the breakdown of marriages and can serve as grounds for divorce in many legal systems. A spouse's infidelity can be a significant consideration during divorce proceedings, influencing both the emotional and legal aspects of the separation.

In Canada, studies show that a notable portion of the population has engaged in or contemplated infidelity. Approximately 10% admit to having cheated, while 22% have seriously considered it. Men are more likely than women to report having had an affair, with research indicating a higher incidence of infidelity among men.

However, many people are unsure of what is considered adultery in Canada, especially when it comes to how it impacts divorce proceedings.

Legally, it refers to a married person engaging in a sexual relationship with someone other than their spouse. Emotional affairs, however painful, generally don’t meet the threshold. And to use adultery as grounds for divorce, it must be proven with credible evidence—messages, financial records, or testimony that confirms the relationship occurred.

Understanding this definition early on can reduce confusion, avoid unnecessary conflict, and help both parties move forward more efficiently.

Financial Implications of Adultery

Adultery can complicate the financial aspects of divorce. In fault-based jurisdictions, judges may take infidelity into account when determining alimony, potentially reducing or denying support if one spouse is found to have had an affair.

However, this outcome is not guaranteed. Judges often weigh multiple factors, including the length of the marriage, each person’s earning capacity, and the impact of the affair on the family. If the unfaithful spouse spent marital funds on the affair, such as hotel stays, gifts, or travel, it may be treated as marital waste. In these cases, the court may adjust the financial settlement to account for misuse of shared resources.

In community property states, assets are typically divided equally. However, if one party can show that the other misused joint finances during the affair, it may affect the division. In equitable distribution states, judges aim for a fair split rather than an equal one, allowing more flexibility to factor in misconduct.

Not every case of adultery results in financial consequences. Some judges focus solely on practical considerations like income, needs, and future stability. Still, when infidelity clearly damages the couple’s financial standing, it can influence how settlements are handled.

Impact on Child Custody Decisions

In custody cases, the court prioritizes the child’s best interests. Judges evaluate factors like age, emotional and physical needs, and each parent's ability to provide consistent care. While adultery can influence divorce proceedings, it holds less weight in custody decisions unless it directly affects the child.

Infidelity alone does not make a parent unfit. What matters is whether the affair disrupted the child's environment or parental responsibilities.

Concerns may arise if a parent introduces a new partner too soon after separation, especially if the child reacts with confusion or discomfort. Another red flag is when a parent prioritizes time with a new partner over the child, missing key events like school functions or medical appointments.

Custody outcomes are based on the child’s well-being, not personal conduct. Courts focus on parental communication, caregiving history, and the ability to maintain a stable, supportive home. Unless adultery interferes with these core areas, it is unlikely to affect custody arrangements.

Emotional and Psychological Considerations

Adultery often causes significant emotional distress. Feelings of anger, betrayal, sadness, and confusion are common and can make the divorce process more difficult. These emotions may cloud judgment and lead to choices that complicate the outcome.

A hurt spouse might push harder in court, driven more by resentment than reason, which can prolong the case and increase legal costs. This tension also affects children, especially if they witness ongoing conflict between parents.

Support during this time is essential. Whether through therapy, support groups, or trusted friends and family, staying grounded emotionally can help individuals navigate the process more clearly and constructively.

Parents should limit the emotional impact on children by protecting them from the details of the situation. What matters most is making sure they continue to feel safe, supported, and loved throughout the transition.

Legal Strategy and Documentation

When adultery is a factor in divorce, legal advice is essential to determine whether it should be introduced in court. In some cases, it strengthens the position, especially if the affair caused financial loss or emotional harm. In others, mentioning it may escalate tension without affecting the outcome.

Proper documentation is key. Evidence such as phone records, emails, or receipts showing the use of marital funds can support claims, but it must be obtained legally. Accessing someone’s private accounts without consent can create legal issues and weaken the case.

Mediation may be a better path for couples who can still communicate. It offers a more private and less confrontational way to resolve disputes. When trust is broken, or emotions are high, court proceedings may be necessary to reach a resolution.

An experienced lawyer can guide strategy and ensure the focus stays on relevant issues like financial fairness and the welfare of any children involved.

Adultery can impact divorce outcomes, particularly when it involves misuse of resources or disrupts family stability. In other cases, its effect may be minimal, especially where fault is not a legal consideration.

Moving forward requires staying focused on key priorities. This includes emotional well-being, responsible decision-making, and securing fair arrangements. With a clear approach and legal support, the divorce process can stay grounded in solutions rather than past mistakes.