If you dream about infidelity that was made by you, then it means you shouldnt stay the way you are. If there is something you did on purpose and it hurt someone you should apologize for it. The dream in which someone is unfaithful to you, shows that you are afraid of losing this person, or do not trust him, therefore you dream about it. Make sure you talk to that certain person about this situation.
Read more about dreaming of Infidelity in other dream meanings interpretations.