I respect your view and beliefs on this subject.
Everybody is entitled to choose his/her path.
I suggest to go the single room route... As opposed to a twin.
Make sure you explain this fully to your g/f / fiancee, as she might not see the point, and think that you don't like her.
I tried to abstain, and only succeded for a couple of days before succumbing to her tears. I am afraid I am weak.
I wish you all the best.
regards
Dom