Dreaming of your girlfriend with someone else means you are insecure about the current relationship where you do not trust your girlfriend’s circle of friends. These insecurities can arise from your previous history of cheating and promiscuous activities.
If a man dreams about his girlfriend with another guy, it signifies that he is having trust issues and his subconscious is telling him there is something wrong. It symbolizes insecurity, feeling betrayed and a lack of self-worth.
It also reflects the current state of the relationship of a couple in a dream. The man may be insecure because he has been given reason to believe that his girlfriend wishes to leave him for another lover. The dream may reflect his natural sexual competitiveness and desire for control in the relationship with the woman he loves.
Learn to trust your girlfriend by being secure about yourself. If she deserves to be dumped, then break up with her.