Ok I stayed out of this long enough.
Empathy is high but sympathy is low here. So now the OP has said that it was a pressure from everyone here which led to the letter and the coming out. As noted in an earlier post letter=bad idea. I reeks of "I am ashamed and afraid." and it is set in stone so to speak. Like the old story about the brother who call another brother and asks how the cat is. The cat died. OMG why didn't you temper that with a story??...same here. Hand spouse a letter, I like wearing women's clothes...everything from then on is moot, world crashes. Given that most people here no longer have the option to come out at the beginning of a relationship. Also a given that waiting for 30 years into a marriage when you KNOW the spouse would disapprove to come out....not a good idea. Seems you could sort of know how they would react by then. This gets back to the "I feel for you but what the heck were you thinking" part. Sometimes slow and steady is better.
So the gist of the "tell her" posts you were reading didn't say slap her in the face (at least as far as I remember...but maybe there was one or two that said that) with the information. Most said talk to her (talk...communicate face to face...not email, not letter, not phone call from a hotel in Baltimore). I know that there were posts that said write a letter...but they meant write stuff down so you could talk.
You know this won't go away. It won't go away from her stand point because every time you go to buy milk she will think you are sneaking out to dress up (and whatever misconceptions she has about what you do then). You can tell her you won't do it. She will KNOW you will. If you can drop this then the whole thing was at least in your mind a game that you were playing. You wore the clothes for fun. Thus why did you have to tell to start with? Wasn't any fun anymore? But if this is truly who you are, you can say you'll quit, you might even succeed at least awhile and then you will do it again. Now it is a sneak thing again, a lie. You will sneak around fearful and afraid and your demeanor will change and you will become unbearable. Then she will start to suspect. Hopefully she will only suspect you are dressing again but in her mind you are cheating, even if you aren't and she will start being unpleasant and now the whole divorce thing comes back up. One or both of you will be unhappy in this relationship.
My soapbox about all this is you had a marriage based on fallacies. You assumed a lot she assumed a lot and evidently you didn't assume the same thing. Dating has a lot of good reasons and it isn't just to get "some" you know. It is when you find out how the other person thinks and feels. Someone wasn't paying attention. Ok so you get married and you both assume that the castle and princesses and princes and no dragons...but you still know how the person feels on certain subjects. They don't like short people or they hate the color yellow. You don't have short friends and you don't buy the color yellow. But when she says something like "Did you see how that guy dressed in that movie? What a weirdo." Pretty god indication you should either come clean then (early) so you both can move on or you live with your secret...until you can maybe slowly change her thoughts on it. Not in one fell swoop.
Now the other point I want to make here is the word Fetish. There is the implied sexual part of this. Or something one does for sexual gratification. That is how we have come to associate the word now (actually a fetish is an object that has mystical powers and often is held to invoke those powers). But to be blunt here, even if some people on this board have a sexual "fetish" for clothes (in other words they have to dress to have sex), dressing in and of itself is NOT a fetish for the majority. We cannot overcome prejudice when we propagate it ourselves.
Sorry for the long post but all the "poor me" posts are really just "feel sorry for me" posts recently and the spouse is cast in the bad person role. Two way street here. Responsibility rests on telling early so the relationship can either grow or fail before your investment is too high