Your Partner Messages a Lot and Spend Most of Free Time on Facebook
First answer to the question “how to tell if someone is cheating on you on Facebook?” is one of the first signs of cheating. If your partner is constantly messaging people on Facebook, but never wants to share any details about it, that’s a big red alert. If it happens once or twice, that isn’t a big deal. But, if this happens all the time, then you should know he isn’t talking just with friends about their fantasy football league or cooking recipes. Also, if they stay up all night talking with someone, or their phone vibrates in the middle of the night quite often, you should know that something isn’t right.