Dreaming of adultery is a sign of negative forces at work in your life as per dream meaning and interpretation. A person should be careful after such a dream. You might give into unethical relationships causing distress and harm to your current life.
Dreaming of adultery with someone you know means you will be cheated soon.
Dreaming of adultery with unknown person means you will give into temptations and this will disrupt your present life.
Dream of adultery and you are not happy in the dream means you will regret an action of yours. This will damage a current relationship.
Dream of adultery and you are happy and you are repeating it or want to see it again means you will have your desire fulfilled soon. But the fulfillment of desires will bring unknown problems.