This section is from the book "How To Intepret Your Dreams", by An Unknown Author.
To dream about sex, refers to the psychological completion and the integration of contrasting aspects of the Self. You need to be more receptive and incorporate aspects of your dream sex partner into your own character. Alternatively and a more direct interpretation of the dream, may be your libido's way of telling you that it's been too long since you have had sex. It may indicate repressed sexual desires and your needs for physical and emotional love.
To dream about sex with someone other than your spouse or significant other, suggests dissatisfaction with the physical side of your relationship. On the other hand, it may be harmless fantasy. In such situations, you may find that you are less inhibited sexually and you can even bring that sense of adventure to your existing relationship.
To dream that you are having sex with an ex or someone who is not your current mate, denotes your reservations about embarking in a new relationship or situation. You may feel nervous about exposing yourself or currently feel a resurgence of those old emotions and feelings that you felt back when you and your ex were together.
Believe it or not, it is not uncommon for people approaching their wedding to experience especially erotic adventures with partners other than their intended spouses. This may be due to the intensity of your sexual passion with your fiance. It also relates to the new roles that you will be taking on and the uncertainty that that may bring.
If you are heterosexual and you dream that you are having sex with someone of the same sex, signifies not necessarily homosexual desire, but an expression of greater self love and acceptance. You need to be in better touch of your feminine or masculine side.
To dream that you are the opposite sex, suggests that you exhibit or need to incorporate those qualities of the opposite sex. Ask yourself, how do you feel being a man or a woman? In what ways can you incorporate those feelings into your waking life?