Cheated on my husband in a dream

Just woke up super disturbed by my dream. My husband and I were traveling back home from a trip. We decided to stop in some random city. I somehow convinced my husband that we should go to a friend's house really quick. We get to this male friends house. This is a guy I went to highschool with. The house is a 3 story home. I told my husband it would be easier for us if he just did some laundry there. And while he did that I went to the secluded top floor with this friend. Then we had sex while my husband was downstairs. This dream was so freaking vivid. I woke up so upset. I would never cheat on my husband so where did this dream come from?? Sometimes I hate that I have such vivid dreams.