I have these dreams, and when I wake up I calm myself down by recognizing that my dreams are based on my fears or desires, and the subconcious. I have dreams all the time on cheating on my fiance, or drinking behind his back (almost one year alcohol-free June 15th =D). I guess part of me feared that maybe if I ever started to drink again I would lose control like always (I would blackout every single day) and do something with someone and only just realizing I am cheating after the fact. So, I have a feeling that your dreams have to do with your past experience and the fear it will happen again, and your fiance also has that fear.