Hopefully, your boyfriend will never actually cheat on you. However, it can't help to keep your eyes open. It's better to figure out that he's cheating than to be shocked when he leaves you for another girl. Here are a few signs that he's been cheating with a certain someone:
1. He Gets Weird when You Mention Her
If he acts weird whenever she enters the room, or when you simply mention her name, then something fishy is going on. There's no reason for him to act out of the ordinary when she's brought up. If she's the only one he acts bizarre around, and he doesn't have any excuse for his behavior, then you should be concerned. He might be cheating with her, especially if she's acting as strange as he is.