i think it has nothing to do with cheating
cheating can only be done in action
dreaming of someone else,
just thinking of another woman/man
or just looking at it is not cheating either..
its just party of having a sexual orientation
and it's biological purpose is to maintain the survival of mankind
without that thirst for sex, mankind would colapse...
your dream liffe is realy personal to you
i dont think there are any rules, and that doing what you want to do is important
if you are able to imagine your gf/bf in your dream and have sex with him/her then fine
but in my lucid dreams where i have sex with ppl, i just pick up the first girl on sight

i think your dream life is so personal that you realy dont have to justify anything you do
if i kill ppl in my lucid dreams, i wont feel bad for it..
its like playing a video game

love

Xavier