To dream that your mate, spouse, or significant other is cheating on you, indicates your fears of being abandoned. You may feel some lack of attention in the relationship. Alternatively, you may feel that you are not measuring up to the expectations of others. Usually, dreams of a spouse having an affair with no real reason to be suspicious should be seen as your own possible insecurities.

Your sister is a close representation of you. If you are feeling inadequate in some way, you may feel that your boyfriend would view your sister as a 'better' version of you.

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Why did your sister's marriage end?...infidelity, lack of sex or sexual desire?
Do you fear you and your boyfriend could break-up for the same reason?
Do you feel that sex between you and your boyfriend is lacking in any way?
Do you feel that you are not sexually adequate, and you fear your boyfriend could be dis-satisfied with you?
Has your boyfriend ever 'cheated' on you in the past?
Have you been feeling decidedly un-sexy, or undesirable?(That this dream is recurring...does it seem to happen on or about the time of your menstrual cycle?)
Have you been wanting to try something different within your sex life....a way to 'spice things up'?
Has your boyfriend ever suggested a 'ménage à trois' with another female?(which is usually a very uncomfortable proposition for you, as his girlfriend...leaving you to feel as though you are not good enough for him, or he is unhappy with you.)

If your boyfriend hasn't given you any reason to suspect he's having an affair, don't take these dreams too literally as they usually highlight inner fears. You may have hidden worries about your sexuality or desire something that's not in your best interest. The dream is a way for your subconscious to express your own sexual urges. Sometimes it does this in ways that may go against what is socially acceptable or advisable.


I hope this helps allay some of your anxiety. Good Luck!