We’ve seen the cheating scenarios play out time and time again: in the melodramatic soap operas, in our favourite Hollywood flicks, and spilling out of trashy celebrity tabloid magazines…and yet we never quite believe that infidelity could strike our own rock solid relationship. Until it does. The sense of hurt and betrayal from discovering that your partner has been unfaithful can be amplified should you discover that the affair has gone on over a long period of time, because you failed to see the warning signs.

Of course, every situation is different, and while no signs are definitive, private investigators are mindful of certain tell-tale behaviours that can indicate a cheating spouse. We’ve seen it all, and PIs have an in-depth understanding of the psychology behind a guilty partner attempting to conceal an illicit affair. Below we share the top 9 signs of a cheating spouse, so that you can prevent being blindsided by a cheater:

  1. Password Protected Electronics

This is arguably the most important sign to make note of, as your partner’s electronics are their lifeline to their other person(s). Note if suddenly they have made their phone, tablet, or computer password-protected when they used to be open to use. Or perhaps the password that they had shared with you in the past, is no longer working on their devices. This can be a sign that they are taking extra precautions to limit the risk of you intercepting a message from another lover. 

Cheaters are careful to carry their phones everywhere (including the bathroom!) and will typically be secretive about their phone and computer use, choosing to “catch up on emails” late at night or behind closed doors where there is less risk of you sneaking a peek at their screen.

2. Sudden Attention to Their Appearance

If your spouse is suddenly taking a renewed interest in freshening up their wardrobe, hitting the gym, and spending a few more minutes primping in front of the mirror, it is possible that they are looking to catch the eye of someone else. A change in grooming habits, such as taking a shower as soon as they come home, can also mean that they are trying to wash away any evidence of their cheating behaviour.

3. Changes in your Sex Life

While it is completely natural for the frequency of sex in your marriage to ebb and flow over time, note if there has been a significant dip or spike in intimacy.

Often there is an unexplained increase in bedroom activity, typically fuelled by guilt. Or perhaps new bedroom behaviours have suddenly been introduced to create a different, new kind of sex. Examples of new sex behaviours can constitute anything that wasn’t present in your sex life before, such as:

  • New positions
  • Sex toys
  • Different, or public locations
  • Talk of adding a third-party into the mix
  • Aggressive/changed dirty talk
  • Interest in living an open or swingers lifestyle

Or perhaps your sex life has dried up entirely. Talk to your partner to see if they have an explanation for the sudden change in your sexual intimacy or behaviour.

4. A Sudden Change in Habits

If you have lived with your spouse for some time, you should be aware of their daily habits. Perhaps they like to bring you a cup of coffee every morning, always walk the dog before work, and read the paper after dinner. While it is normal to change our habits over time, certain habit changes can be indicative of cheating behaviour. Perhaps your partner has taken up a new hobby that demands several hours of their time each week. Or maybe they have suddenly stopped saying “I love you”. A series of habit changes over a short period of time can be a cause for concern.

5. Changes in Attitude

While a change in attitude can be brought on by a number of different factors such as stress at work or health issues, typically cheating spouses will also exhibit noticeable shifts in attitude or mood. Cheating partners will sometimes experience unexplained mood swings, ranging from hostile and frustrated, to overly affectionate and bubbly. This can be attributed to the combination of adrenaline and guilt felt by those having an affair. Insecurity and a sudden dip in self esteem are also common among cheating partners.

6. Lying, Avoidance, and Insincerity

While a cheating spouse will inevitably attempt to cover up their tracks with a steady flow of little lies, in time, many will also become deflective and defensive when questioned about their behaviour. Even an innocent question (such as “how was your run?”) will trigger an unwarranted emotional response, a result of the spiraling guilt and stress from their tangled web of deception.

Over time, to avoid these lies entirely, a cheating spouse may start to distance themselves from you, responding to questions with one-word statements, and no longer engaging in what was once an intimate rapport.

7. Periods Where your Spouse is Unreachable or unavailable

If there is a spike in the number of periods in which your spouse is unreachable, beyond work hours or during times in which they would generally be responsive, it may be indicative of cheating behaviour. This may be a stronger red flag if your spouse is defensive or unresponsive when questioned about these absences.

8. Unexplained Credit Card Charge or Hidden Statements

Almost always, unexplained credit card charges will start appearing on your wandering partner’s statements. More often than not, statements suddenly are rerouted to work addresses, or they have now decided to go paperless, leaving no trail for you to follow. 

Many cheating spouses will have enough foresight to not make a purchase for their other significant other on your shared credit card. Some will instead start making more frequent trips to the ATM, to ensure that they always have cash handy for such expenses, like a meal at a restaurant, or to pay for a hotel room. If they used to be obsessive with collecting points on their credit card and now have a thick wad of cash in their wallet, it may be worth questioning them about the change.

9. Check your Tech

Thanks to technology and social media, we’re now more connected than ever before, with our lives documented and displayed for everyone to explore. When a spouse is trying to conceal incidences of infidelity, generally they’ll make an attempt at covering up their tracks online. They will ensure that social media accounts are private, and will repeatedly clear the browser history on your computer. Sometimes, to make themselves seem more available to lovers outside of the home, they will remove any pictures of yourself or your children from any online profiles.


The consistent thread through each of these warning signs is the notable change in activities, character, attitude, and behaviours of your partner. While we are all predisposed to growth and change over time, a series of sudden, unexplainable changes can be an indicator of something worth questioning. 

If you’ve tried to reach out to your partner about your suspicions and are unsatisfied with their response, it may be time to seek the help of a trusted private investigation agency experienced in spouse, relationship, & infidelity investigations.  With a long-standing reputation as Toronto’s leading Private Investigation Agency, our expert team at Star Quality Private Investigations® will help uncover the answers you need and deserve.  

Knowledge is power: call us today and let the SQPI team help expose the facts behind your suspicions.