I came out to my wife of 12 years about 2 months ago now, after several months of therapy. It was rough, and the first couple of weeks sucked bad. She actually moved out for a bit. It's still not good, and neither of us know where this will end. She is my best friend, and I would like to believe I am hers. She is attracted to alpha males, and until a couple of months ago, that was the role I played well. She is definitely not into women, and has said it is nothing personal - she has supported my transition, and even encouraged me to do laser and go to a gender clinic to discuss HRT. However, she does not want to be married to a woman, is in no way a lesbian, and has been up front that she thinks she will leave if I transition beyond cross dressing (which moves her boundaries pretty far) and minor body changes.
I came out in a really controlled setting, with the help of my therapist, and with a ton of support materials on hand. It still went about as bad as you can imagine. My gentle wife, who has never said an unkind word to me, started dropping f-bombs and got very violent. It reflected the hurt and deep pain she was feeling (and still feels to some degree).
I wouldn't change coming out, and I feel more at ease with myself now than ever in my entire life. In a lot of ways, though, life has become a lot more complicated. Work is a challenge now, as I have to balance appearance. My wife is probably going to leave me. I have had mixed reactions from friends, and been outed to a professional colleague. Big changes, and I have barely begun any transition.
I offer this not to dissuade or persuade you of anything. I only want to share that in my experience coming out removed a lot of the "noise" and energy swirling in my head, and has allowed me to think more clearly than ever. However, it has come with an immense cost of pain to myself and others, a host of personal and professional uncertainty, and a future that is just as cloudy. Talk to your therapist before coming out is my advice. Get some books and resources lined up for your wife. Look at some of the guides online here - they are very helpful. Be prepared to be outed to others -- your wife may run out the door in tears and tell her friends because she will need her own support, as mine did -- and they will tell others. And go slow.
Good luck. This is not easy, I know. You are not alone.
Toni