well since my experience i dnt do anything like that.
nothing remotely close to cheating, not even flirting.
it was an extremely painful experience and it too two years to trust another woman and get in a relationship.

but i do like adult movies and sites.
but i do browse these sites etc with my last two girlfriends,
we enjoyed it together so i did not feel guilty, and we never made personal contact with anyone so it was ok

my last girlfriend was not much into these things but she was allways with me even if reading a book while i surfed.

i dont think i would do any thing behind my future girlfriends back either