What does it mean to have a dream of your partner cheating?

The dream suggests that the dreamer has doubts about either the partner or about one's self. The dreamer could lack confidence in his/her worthiness, and that lack of confidence could be transferred to the partner in the dream. Alternatively, the dream might refer to the partner's other time commitments, perhaps with family or a job. Any activity that takes the partner's time or attention away from the dreamer could appear as "cheating" in a dream.