I have to run and don't have time to check on the other responses till later so maybe someone already mentioned it?
I imagine your wife is of a similar age as yourself? Before you cough up good money for a therapist, try this. Google Dear Abby or Ann Landers and do some type of search for men CDing. More likely something like "men wearing women's clothes". I believe they were sisters and "reliable" sources of info for 10 or 20 years, maybe longer when newspapers were still king. Your wife's concern was a VERY common one that ladies wrote in about and this was longggggg before easy ordering off the internet. Along with the anonymity factor.
Even back then, CDing was obviously a very common thing. Today with the internet and all that it allows, it's very easy to see [for anyone with an open mind] that CDing MtFs is likely several times higher than the incidence of gay people.
CDing IS a part time deal for the vast majority of MtF CDers. In fact, a "hobby" for most.