I am so sorry for the loss of your wife, best friend, and partner in life. I basically agree with what Lori said and I think those are very wise words. I also agree with Char that we all react to such losses in different ways in spite of the mourning process forming some kind of general sequence of stages. Don't fight those feelings - if you feel like crying your eyes out do it. You are you and that is what you must be whatever that is.
What Helen refers to is the norm. Trauma can cause major changes in your desires to do this or that. When you are focused on the loss of your mate you are mourning that loss and not doing a lot of thinking about the things that can play a role in defining you. That includes expressing your gender clearly no matter whether you are male-like or female-like or some kind of blend unique to you. It is just not a priority right now. As Helen says and as the experts in this say, just because you do not feel a desire or a need does not mean it has gone away. It will come back to the forefront in awhile - maybe the same or even stronger. It is not predictable other than the probability that Marcie is still very much there and quite possibly is involved in the mourning in a way that you may not recognize.
Hang in there; it will get better. And looking at your avatar I can see you make a beautiful woman, not just outwardly but also inwardly. Allow her to do what she needs to do which is far more important than the clothes and looking the part. You have had that identity, probably, all your life. It may be mixed with male-like aspects - that is perfectly alright. My thoughts are with you.