Private Investigators in Infidelity Cases: What Lawyers Recommend

Why Infidelity Still Matters in Ontario Divorce Cases

Infidelity is often an emotionally charged issue for couples, and while Ontario follows a no-fault divorce system, it can still play a role in certain legal matters. Under the Divorce Act, couples in Ontario can obtain a divorce without proving wrongdoing by either spouse. This means that simply proving that one partner was unfaithful is not enough to receive a more favourable property division or spousal support order. The legal test for divorce is usually a one-year separation, regardless of the reason for the marriage breakdown.

However, there are specific circumstances where infidelity becomes legally relevant. For example, if a spouse has used family money to fund an affair — such as paying for hotels, gifts, or travel — this could be considered financial misconduct and factored into an equalization payment under Ontario’s Family Law Act.

A common misconception is that infidelity automatically results in higher spousal support or a larger share of property for the innocent spouse. In reality, Ontario courts focus on fair financial outcomes, not punishing bad behaviour. Spousal support is determined by need, means, and the length of the marriage — not by moral blame. Property division is based on the equalization of net family property, which generally does not consider who was “at fault” for the marriage breakdown.

When Lawyers Recommend Hiring a Private Investigator

Family lawyers in Ontario do not automatically suggest hiring a private investigator in every divorce case, but there are specific situations where professional investigation can strengthen a legal strategy. A private investigator provides objective, court-ready evidence that may be difficult for a spouse to gather on their own.

One of the most common scenarios is when proof of infidelity is tied to financial misconduct or cohabitation. If a spouse is suspected of spending significant family funds on an affair, a private investigator can help document those expenditures through surveillance and financial tracing, which may affect equalization payments under the Family Law Act. In cases where a spouse is allegedly cohabiting with a new partner, concrete proof can be crucial because it may reduce or end ongoing spousal support obligations.

Private investigators are also valuable when there are concerns about hidden assets or undisclosed income. Skilled investigators can assist lawyers by uncovering property records, bank account activity, or business interests that a spouse failed to disclose during financial disclosure — a critical step in ensuring fairness in property division.

In custody and parenting disputes, investigators can document behaviour that may pose a risk to children’s safety, such as substance abuse, neglect, or inappropriate individuals being present during parenting time. This type of evidence can support a parent’s application for supervised access, changes to parenting arrangements, or even exclusive possession of the matrimonial home when it is in the best interests of the children.

How Lawyers Use Investigator Findings in Court

Once a private investigator completes their work, Ontario family lawyers carefully evaluate how to use the findings to advance their client’s case. Evidence must be presented strategically to strengthen parenting or financial claims while respecting Ontario’s legal standards.

In custody and access disputes, investigator reports can be powerful tools to demonstrate concerns about a parent’s conduct. Lawyers may use photographs, videos, or witness statements to show that a child was exposed to unsafe conditions, neglected, or placed in situations contrary to their best interests. This type of evidence can support applications for supervised parenting time, changes to decision-making responsibility, or even exclusive possession of the matrimonial home if it helps create a safer environment for the child.

In financial disputes, lawyers often rely on investigator findings to trace misuse of family assets or confirm cohabitation with a new partner, which can impact ongoing spousal support obligations. Reports documenting extravagant spending on an affair, undisclosed property ownership, or hidden income sources can be presented in court to seek a more equitable division of net family property or adjust support payments.

Outside of the courtroom, investigator findings can also be highly effective in settlement negotiations or mediation. When the evidence is clear and credible, it can motivate the other party to reach a fair agreement rather than risk an unfavourable court decision.

By aligning investigator findings with Ontario’s legal framework — including the best interests of the child test under the Children’s Law Reform Act and the financial disclosure obligations under the Family Law Act — lawyers can build compelling, evidence-based cases that help judges make informed, just decisions.

Practical Tips for Clients Considering an Investigator

Before hiring a private investigator, it’s important for Ontario clients to approach the process thoughtfully and strategically. The first step is to choose a licensed, reputable investigator. Under Ontario’s Private Security and Investigative Services Act, 2005 (PSISA), investigators must hold a valid licence to operate legally. Working with a licensed professional ensures that evidence will be gathered ethically and has a higher chance of being accepted in family court proceedings.

Clients should also discuss their objectives and budget with their lawyer before moving forward. A good family lawyer will help clarify what evidence is actually needed to strengthen the case — whether it’s proof of cohabitation, documentation of financial misconduct, or surveillance related to child welfare concerns.

Finally, clients should keep in mind that the ultimate goal is to support resolution, not escalate conflict. Using an investigator is not about revenge or embarrassing the other spouse — it’s about presenting clear, lawful evidence to achieve a fair outcome.