Adultery in dreams does not foretell pleasurable situations anytime soon.
If you see in your dream that you commit adultery, and this is not the case in real life, the dream acts as a warning for imminent frictions and unpleasant situations in your relationship. Tread carefully and make sure you pinpoint the problem at hand, to restore the balance in you and your other half.
The latest interpretations of adultery take into account for a proper analysis, our psychological state and significantly less the symbolic - prophetic meaning of a dream of infidelity - adultery.
So, if you see such dreams - nightmares you have to approach the reasons behind said dreams methodically.
It is possible that your insecurity plays an unfortunate role in your state. Or perhaps you subconsciously realize that your relationship is actually not as stable as you let yourself believe it is.