Cheating can take on all forms: Sexual infidelity, financial cheating, emotional affairs. But nothing makes things easier than technology. Cheaters have gone high-tech. When their behavior shifts, you have to pay attention.
Sign #1: They always logout of Facebook.
We all spend a lot of time online. Technology is now a part of our culture and daily lives. Because of that, it's rare that we consciously log-out of social media sites and services. Maybe you will on a shared computer, but not on a private phone. If they are randomly logging out of Facebook, perhaps they are careful with privacy.... or they are hiding something.
Sign #2: They jump on their phone first thing in the morning... usually in private or in the bathroom.
Because we are all so connected, it's [unfortunately] not unusual that people sleep with their phone nearby—perhaps tracking sleep patterns, or they fall asleep to meditation or music—and many reach for their phones first thing in the morning. However, Facebook cheaters might grab their phones first thing and disappear to the bathroom. Or they are on their phone when you wake up, and they quickly put it away—or switch applications.
Sign #3: They are highly possessive of their phone.
Lots of activity on their phone and online, but they never really have anything to say about what they are reading, writing, doing, or texting. When they are online, they are beyond distracted. When they are off their phone (finally!), it's either placed face down right next to them, or it's in their hand/possession. And if you even glance at it, they will either get a weird, guilt look on their face, or immediately ask you, "What? What's the problem?"
Sign #4: Lots of new friends, and new likes and comments.
We all have friends online who we don't really know very well, and many times have never met in person. As such, it's unlikely we would know all of our partner's Facebook friends—to include coworkers, colleagues, college friends, etc. However, when lots of comments and likes start coming in from someone new—and usually just one person—it's a red flag. if you start reading little quips and inside jokes on their Wall and you have no idea what they are talking about, something is amiss.
Sign #5: Instantly defensive and ready to fight.
As with most cheaters, people who use Facebook for illicit affairs are ready to defend themselves—and perhaps even blame you for acting weird, disconnected, and whatever they deem as suspicious behavior. If you question any of their activities or behavior, they will likely shift the blame, manipulate the conversation, deflect your accusations, get angry and defensive, or leave.
While these signs aren't a 100% foolproof way of detecting if your partner is Facebook cheating, they are sure signs that something serious is off in your relationship. Bottom line: Follow your gut instincts.