I am single myself as well, and it's been years since I had a so. Those days, I was still all the way closeted, so being a cd and having a relationship at the same time was more a problem for just myself. Still, the cd doesn't change who I am and who I love. I am heterosexual and if I am with a woman that I love, my feelings for her wouldn't be different when dressing up.
However things might become harder in a relationship when coming out. And I can understand very well that many ggs might have problems with cd. Like said before, they could feel like they only have a parttime husband. But that's all a matter how she feels about the whole cd subject, how far we feel like we need to go with our cd around her, and what sacrifices we are willing to make...