An easy way to keep two romantic lives separate is to buy two separate phones. That way, the cheater doesn’t get confused and text the wrong person by mistake. The existence of this second phone is also a liability, even if it is described as a “work” or “emergency” phone.
Another technique is to purchase a separate SIM card, which can be switched out of phones that have been “jail-broken.” This is a lot of work and unlikely for most cheaters, but if you find a SIM card lying around, you may be able to extract its data by inserting it into another phone.
Any new entries for people or companies you are unfamiliar with could be a ruse. Call the number and see who answers. It’s a good idea to block your number. Tap or click here for 5 ways to block or hide your number when making a call.
6. Check the phone’s locations
As we become more reliant on GPS, you may also want to take a peek at your spouse’s location history. For Google users, the “previous destinations” menu option on the navigation system may chronicle your spouse’s movements; for Android users, the Google Timeline feature (found in the Google Maps app or Google Maps online) functions similarly.
If your spouse uses an iPhone, there is one place to be sure to look. Many people don’t even know this treasure trove of tracking exists.
You can find an iPhone user’s frequent locations in Settings, Privacy, Location Services, System Services and then Significant Locations. It takes a fair amount of effort to disable or delete these types of settings consistently, so if they are up to no good, you’re likely to find something.
You may want to turn off this feature on your own phone if this practice creeps you out. Tap or click here for steps on how to do it.
7. Find their phones
Many popular devices utilize some form of location technology and often it’s easier to have the service turned on than to disable it. If your spouse uses an Apple device connected to a family account and has enabled location sharing, you can locate their device by logging on to iCloud and clicking on Find My iPhone or using the Find My Friends app.
If your spouse uses an Android phone and is logged on to Google on a shared computer, you can type “Find My Phone” into the search bar, and you’ll be provided with the phone’s location. Other services such as Life 360 offer similar tracking.
8. Search every letter of the alphabet
Cheaters would have to be pretty stupid not to clear the search histories on their browsers. If they routinely access dating sites, especially hook-up services like Ashley Madison and AdultFriendFinder, they will probably think to cover their tracks, 
unless they like flirting with disaster as much as attractive strangers.
Auto-fill is harder to remember. Search engines like Google do a reeters, based on everything you have ever searched before.
If you share a computer with a suspect spouse, you may intend to type “Megalodon” and instead, the words “Megan Granger home phone number” flash across the field. Take this a few steps further. Start typing each letter of the alphabet and see what pops up.
9. Check battery usage
Cheaters typically use a phone because it’s easy to hide and always in reach. You can learn a lot about a person by looking at his or her phone’s screen time and battery usage.
On an iPhone, open Settings, Screen Time and then, See All Activity. You’ll see what apps were used and for how long.