My wife now knows and I'm a bit confused...

[linda allen]

I would NOT write a note.................. .

I agree. Never put anything in writing that can possibly be used against you at some point.

A note telling her how much you love her, how much you appreciater her, etc. is fine. It's good actually.

A note explaining why you dress up in women's clothes is not a good idea.

[Jenni Yumiko]

Agreed there is a big difference between panties and presenting yourself. D not write a letter to her, but write down everything you want to say and organize it clearly.
Use a serious tone, wait until she gets back and face to face.
You have a long road ahead of you, good luck!
I also was just recently down your road, and currently we are in stasis. :-(