Does your wife say things like that to your C? If so, does C contradict her, or validate what she says?
Your wife is an intelligent woman.... I can't believe she really believes what she's saying. Maybe the best way to change her mind is to call her bluff, and find someone she knows (family member or friend, there must be someone) who meets the criteria. Unfortunately, she probably wouldn't look favorably on an email from any of your imaginary friends here, horny though they may be....