This is not uncommon at all. You found something that satisfied your need at first, but the farther it went the more you needed.
There is no such thing as a "true" TS. Yes, I've heard the argument many times, but it really is a crock of shit. If you have the need to live the rest of your life as a woman you're most likely a transexual. Breast implants or not.
I wish I could say it was that easy for her. It's just not and a lot of factors play into that. The way she was raised, her views on marriage and commitment, her love for you, and her relationship history as a woman. And that's just a few. There are A LOT more.
As a wife of a TS, I can only tell you what helped me. Tell her how you feel. Not what you want to do or plan to do, but how you feel. Then give her time and listen to her. She will, and most likely already is, going through the stages of grief. If she isn't already seeing a counselor, suggest that she get one. Later, if she's interested, there are a few books that might help her. PM me and I'll give you a short list. Be kind to yourself and her right now. She's probably not talking from a rational place right now, but one born from fear and pain.