Dreams dictionary: Threesome
Dreams dictionary: Interpretation 1
To dream that you are involved in a threesome indicates that there is a missing component in your sex life. Pay attention to the gender of the participants in the threesome. If mostly female, then the dream implies that the missing component may pertain to some emotional aspect of sex. If mostly male, then the dream implies that some physical aspect of sex is lacking. Note that the dream does not necessarily mean that you want a threesome in your waking life.