Try the Old School Approach
Here is the one more suggestion on how to tell if someone is cheating on you on Facebook that is well-known to all of us. Get ahold of your partner’s phone or computer when they are not around. If you manage to access their phone or computer, you will maybe find they are logged in and then you can snoop through their profile. This is how most people find out that their partner is cheating on them. Before doing this, you have to be ready for what you might find out. If they are cautious enough to log out, then check through their browser history and maybe you’ll find something useful.