Cheating 
To dream that you are cheating on your spouse, mate, fiance, or significant other, indicates that you have let yourself down in some way. You may have sacrificed your morals and ethics and received little or no benefits in return. It may also represent your increasing desires or fantasies regarding sex. Often, those who are about to enter into matrimony may dream about sensual encounters with other people. This may symbolize the anticipation or apprehension regarding this relationship.
To dream that your mate, spouse, or significant other is cheating on you suggests that you have anxieties about being neglected and deserted. Perhaps you don't feel as if your partner is giving you his or her complete self. On the other hand, this dream might evolve from the feeling that you are not good enough for your partner. You lack faith in yourself or others. It may also mean that you sense your companion is not revealing his or her true character or personality to you.
To dream that you are cheating at a game is an indication that you are trying to avoid certain aspects of your own personality. You don't want to admit your flaws or weaknesses.
Adultery
To dream that you've committed adultery means that you could have sexual desires or be sabotaging yourself. This likely comes from the root of your subconscious mind. You could be drawn into an issue that is not within your best interest such as a legal situation.
To dream that your mate or spouse has cheated means that you have concerns about abandonment. You may sense neglect within your own relationship. You could also feel as though you're not living up to what others want from others.
To dream that you are cheating with your friend's friend means that you're probably feeling forsaken by your own self.
Flirting
To dream that you are flirting indicates that you feel a desire for more intimacy and affection. You may be ready to enter into a serious relationship in the near future.
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