Hi Lisa
Welcome from me, I am a SO too and my partner is looking to start HRT soon We also have 2 kids (teenage) but he doesn't want to go public or for them to know. We have to see what changes occur from the HRT.
I have spent most of the time since I found out in a total state of fear, denial, anger and indescribable sadness, with occasional moments of acceptance in between, which, with time, are getting more and more. I do know how you feel. I would still give anything in the world for this not to be happening, but it is, so I have to learn to accept and support my partner, as I love him dearly and couldn't imagine a life without him, whatever packaging he comes in!
The first thing I'll ask, is are you both having therapy? That really helps a lot, including couples therapy. This will not only help your husband work out where/what he is on the gender spectrum (and there is a spectrum), and will help you to work through your feelings too.
I also cannot emphasise highly enough how important open and honest communication is between the two of you. I only found out about my partner after a couple of years of secret cross dressing. He was too scared to tell me. You both need to talk and share your emotions. Don't hide from him how you are feeling, and neither should he hide things from you - good and bad. My partner and I have found a new closeness through all this, which is one positive.
What is your husband planning? Has he come out socially yet to anyone? Is he planning to? Does he want to have surgery eventually?
I would also advise taking things as slowly as possible on your husband's part. It needs to be at a pace that you are both ok with.
I will PM you too.
Syl