One of those buzzphrases that gets thrown around a lot these days is "emotional cheating". It's not just about the physical act anymore, but about having an intense emotional bond with someone else. A bond that might just be better and more fulfilling than the one they're having with their partner. There's one major problem with emotional cheating, though: how do you know when someone's crossed the line?
Well, if she's cheating on you, she's forming these emotional bonds with someone else by opening up to them. She's sharing her highs and lows, fears and dreams, and you'll be able to tell that because she won't need to share them with you anymore. She's got a new sympathetic ear to whisper sweet nothings to, and maybe even share a bed with.