Guide for Husbands of Female to Male Transvestites
While a great deal has been written about male to female transvestites, there isn't much information out there on female transvestites. A large part of this is likely due to the fact that in modern western society it's much more acceptable for a woman to dress in male clothing. If a woman enjoys dressing as a male, she might simply be seen as "tomboyish" or mistaken for a butch lesbian. While a woman finding her husband in a pair of panties might raise some eyebrows, a man's wife wearing a pair of boxer shorts is less likely to do so.
The fact that they aren't often written about doesn't mean that they don't exist, though, as you and your wife surely know now.
Finding out that your wife is a female to male transvestite is likely to be a shock and leave you with a number of questions. While this guide will answer some of the basics, remember that the person who can best answer your questions is your wife.