"If he visits crossdressing social evenings, should I go?"
Sadly, lots of crossdressers stay "in the closet", and this makes for a lonely life for both of you. Many do manage to meet one or two close TV friends. But it is much better if he can get out and about.
There is especially nothing to fear about him going along to a social meeting of trannies. Great care is taken to make these safe and welcoming places. There is no pressure for him to crossdress, or to give his real name (most assume a female name). Remember everyone there was a first-timer once, and they will help his confidence. For those that have been before, it is just like any other ladies' night at a private house or pub / club.
Help him be ladylike!Many wives and girlfriends do also go, if only out of curiosity. They often meet other women there to talk to, and gain much useful information and support. You may see a few appallingly dressed men, some of whom have complex problems far worse than your partner's. Most though will be happy, attractive, passable as females, and really lovely people to know. There are often changing facilities there if he is worried about travelling "dressed". A one-to-one meeting beforehand, or a reassuring 'phone line for either of you, will also be available.
"I'm worried that he looks too trashy."
Not quite right.If he has the wrong image then change it! Restrain his temptation to try to look like a film star aged 18 (even if he is 18)! Show him how to sit with legs demurely closed, how to walk and move more daintily without looking 'camp', and feminine hair removal.
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