So you think your partner is simply acting differently but you can’t figure out why. You know something is up but just can’t put your finger on it. Maybe he or she is having a rough day? Maybe they are going through a mid-life crisis? Or, maybe, just maybe he or she is cheating? Here are some signs that may raise some red flags and, while they may not be foolproof signs of cheating, they may be enough for you to demand a sit-down conversation.