"OK, so the disclaimer is that CDs say they only feel this way when they are in femme mode, not guy mode, therefore the wife is not affected. But how many CDs have said they feel flat sexually in drab?"
Some say that, not the majority. And of the ones who are married, seems to be a minority who as I said are the types who'd be finding an excuse to cheat regardless of being a CD. And/or they've got issues with their sexuality, and pretend they're Sybil when they're not, using it as an excuse to have their cake & eat it too.