There are many different ways you can try and find out if your other half is being unfaithful to you, many of which depend on if you wish to invade their privacy and if so how far into their privacy you wish to pry.
One of the most common options is to hire a Private Investigator to carry out Matrimonial Surveillance who trails and reports back on your other half to you with any evidence, such as photographs or receipts for places they deny visiting or bills that they say do not exist. Many Private Investigators also offer Web Tracking and Phone Monitoring to allow you to monitor if they are using any technology to keep any secrets from you!
Other steps you can take is Mobile Phone Tracking, if your other half has a Smartphone then you may wish to install a remote GPS application that uses the phones internal GPS and data system to feed back their location to a website that you can monitor. If he says he is going out for some Milk and Sugar is that really what he is doing? Now you can know!
Although many people think this can be malicious and intrusive it can also be reassuring for anyone that may have suspicions that shouldn’t, after all men can be shifty and erratic even when there is nothing going on!