I've noticed that people flirt with you so much more when you're in a relationship. And from talking with female friends about it, it's about them feeling you're safe because of it. I understand it but don't like it, flirting with someone you know is in a relationship is ficked up. I've never cheated and never will, I've ended friendships because of it (them cheating on their partner). It's just so fucking evil IMO, I'd break really badly if someone ever cheated on me.