I see people saying that they suggest or advise you to tell her. I wont do that. I will tell you to tell her. Not for her sake. Yours. Here's a thought, you're sitting there watching TV together, and something about crossdressers comes on TV. She makes a comment about how disgusting that is. As irony would have it, you were about to tell her. So now YOU are left with the decision. Do you regress who you are as a person, or do you end it with the one you love? I can only assure you, after 7 years with the wrong woman, the latter is much easier.
On that note, I vowed never to get involved with someone on a serious level unless they knew. My GF now, I told her before we even slept together. Of course she had lots of questions, including the expected, "Do you want to be a woman". And you simply answer them.
Now I find her asking my why I havent dressed up in a while, and her telling me how much she likes it.
My point is, there are alot of women out there. Some will like it some will not. They are very different. But unless you feel like you can supress everything that you have struggled with and all you have overcome internally as if it doesnt matter, then you will only set yourself up to get hurt. Hurt by yourself for not being true to yourself.
If you need time, tell her. If you need space tell her. But for your sake AND hers, tell her!
Otherwise what kind of relationship do you expect to have?
They say its easier to have loved and lost never to have loved at all.
Frankly, "They" are a bunch of idiots. Most people do not meet someone they really love and mix well with. WHY? They settle for someone they are "comfortable" with.
I am not saying you're "comfortable" but you're contemplating waiting to tell her, or not tell her at all. I would start there and ask yourself why you havent told her yet. Fear? Fear of what? That she might say "oh hell no" and you don't marry her, thus continuing in your life and pursuit of happiness and allowing her to do so also.
Ultimate point is, you have to decide what you want out of your life. If crossdressing is a part of you, and from what I can tell a big part, then you have to be willing to let whomever you're with in to that part of you.
You cant piecemeal yourself and hope to find happiness. You either accept her as she is and she likewise or be done with it.
Sorry to be blunt but I think thats what you should hear.
__________
From my girlfriend:
I think it's better to know early. It's a big step and requires bravery, but it will be worth it in the long run. I can't say that I would have responded favorably to a TG movie or that I would be attracted to it in another man. I am very curious to find out what the motivation is behind crossdressing as I have never been exposed to it before now. I'm starting to enjoy it - it's fun going shopping for clothes and makeup together - but it's more important to me that Skye is happy. Skye is a rare mixture of masculinity and femininity that you don't see in one person very often. One day she is more masculine than most males I meet and another day she is softer and sweeter than most females. I am captivated by the journey, and I hope I am around for years to come.