Oh Kimberly,
I know this story all too well. I didn't have the advantage of "coming out" on my own terms. I was caught and had to explain.
Your wife's reaction troubles me, and yet it's perhaps understandable. It will take a lot of patient education and learning together to convince her that gender is a characteristic separate from sexual orientation. There are a vast number of heterosexual straight crossdressers. I'd almost venture that most CDs are straight males (without know the true stats). My wife had the same negative assumption that CD or trans means "gay" . It won't be easy to overcome but with patience and love you can do it and prevent panic.]
The other thing that will be difficult ( but not impossible ) to re-establish is TRUST. OK, admit it (you did). You hid something and successfully deceived your partner for many years ..... in her mind. It isn't cheating. I recommend that you attempt to make her realize WHY and HOW DIFFICULT it would have been to openly share your secret. It could have meant loss of your family that you love, your career, job, local reputation, etc. You were almost required to conceal it.
Good luck. You will find great advice for getting together with your wife on this and not letting it damage your relationship too badly. You're relationship has changed forever and there's no toothpaste going back into the tube. Same thing happened when I came out. My relationship with my wife of 40 yrs changed, and hasn't been the same since. Its not hurt or wrecked, and we've come a long way to living with my inner girl. But it can never be what is once was. I instead to think of it as an opportunity for growth.