I had a dream I had sex with another girl who isn't my girlfriend.
Dreams about intimacy or sex with someone who is not your partner can be quite common and often do not have any literal meaning. Instead, they could be reflective of other thoughts or emotions that you may have in your waking life. In this case, the dream may suggest that you have certain desires or attractions that you may be exploring in your subconscious mind. This dream does not mean that you should take action on your desires or cheat on your girlfriend. However, it could be useful to examine your feelings and thoughts towards your current relationship and/or your sexual preferences.