If the partner in your dream was a total stranger then the dream may be much more personal and profound. It could be telling you something about the relationship that you have with yourself by giving you clues about the nature of your unconscious.... The Bedside Dream Dictionary
It is warning you that if you do not, you will suffer the consequences.
If you are the cheater in your dream, you may have a guilty conscious about cheating that has nothing to do with love.... Encyclopedia of Dreams
If an actual lover is the one being unfaithful, then this indicates the dreamer’s insecurities over the relationship.
The partner may or may not actually be unfaithful, but either way the dreamer needs to deal with her feelings.
If an unknown figure is the one being unfaithful, then the dreamer needs to be more discriminating with regard to who she calls friend. Astrological parallel: Mars/Pluto combinations Tarot parallel: The Devil... Dream Explanations of Astro Center
If it refers to your sentimental relationship, the dream denotes deception and unsatisfied needs.
If your partner is the one who is unfaithful, it may mean that you are denying their emotional desires.
Oneiric superstition says that this dream expresses the opposite. It promises a happy relationship, full of fidelity.... The Big Dictionary of Dreams
If you discover an infidelity in a dream, you may want to consider areas in your life where you are avoiding taking care of yourself.
If you are engaged in an affair, you might need to examine your life circumstances for signs of being manipulative or indirect in getting your needs met. As getting caught is always reflective of an unconscious desire to effect a change, being discovered as being unfaithful could indicate a desire to shift some area of your life. Always be willing to look at issues of responsibility when this dream image appears. Where in your life are you not allowing yourself to be accountable for your actions? If the dream involves details of constructing an affair, you may want to examine how genuine you are being in terms of expressing and manifesting your desires in life, both relationally and otherwise. Where in your life are you not being authentic? How might you be betraying your own needs? It is safe to assume that this image in a dream indicates a theme of intimacy issues in waking life, no matter what the marital state of the dreamer. This may have literal implications if you are actually involved in an affair or believe your partner to be.... Complete Dictionary of Dreams