You never want to happen to you, but the unfortunate reality of love and relationships means that at some point in your dating life, you are probably going to be cheated on by a partner. When the cat is let out of the bag, it can feel like that worst thing in the world, and I bet that in that moment you wish you could have seen things coming more clearly than they actually did. To help you get ahead of the heartbreak, here are twenty signs that your partner is cheating.