I had a dream that my girlfriend?

First, may I say that there is certainly a lot going on with you about this particular female and must be "haunting" you at every turn. This particular female appears to have impacted you far greater than many other females in your life and this is "scary" territory for you to emotionally navigate. Therein lies the "biological" aspect to release the anxiety through the dream process. Your "girlfriend having sex with somebody else" is a "symbol" and represents an emotion or in this dream, multiple emotions "you" are experiencing on varied levels. It is but a "thought" that centered at the core of your anxiety is "your" fear that if you proceed to vest your "heart" "emotions" that "you" your heart/emotions may suffer with rejection. The emotions centered in the dream symbol (girlfriend having sex) are centered within the "self doubts" of being inadequate, inferior, unlovable, "lack of" or "being unable" to fulfill what "you" perceive the expectations of or needs of the other individual. Hence, fear of rejection. You have not provided any facts/statements to indicate that this person "cheats", "lies" or has no credibility. -- It is apparent that you find this individual physically attractive and believe that others find her quite desirable, i.e.,referencing your emphasis "high class escort". There is a "discomfort" zone in the emotional "scary" water you are navigating with this woman and this has generated "anxiety". -- You have identified yourself as "conservative" and identified the female "dresses kinda slutty at times". Again, this is but a thought -- maybe this is about "esteem" and view of oneself. The question returns as to "whose" esteem is being challenged in your dream? -- What is it that you seek with this "woman"? "Why" pursue a relationship with this woman if "something isn't right"? Things don't get more right if based on "wrong" to begin with. -- My best to you regarding this matter.