Try cross-posting to Spouses of Transgender

You are not alone. For each transgendered person there are family members looking for understanding, information and guidance. It is not easy to fully understand a transgendered person's reasoning to transition, it is a NEED to be a woman or a man that burns inside. It is telling your husband his mind does not match his body. He has tried to exist as he was born, doing those things that come from being male, but still his need to be a woman continues all day and all night.
You did NOT do anything wrong! It is NOT your fault he wants to transition AND he has NOT lied to you or tried to mislead you. His intentions were true.
Probably the best thing you can do right now is seek information online. I would recommend psychology associations, transgender information sites and groups in your area. Usually an organization that deals with trans people usually have support groups for both the transgendered person and family members. Use them. There are also a number of books on the market which may help. One is "She's not there: A life in Two Genders by Jennifer Finney and she also has a number of videos on YouTube. Seek and you shall find......
Lastly as difficult as it may be for you, sit down and discuss this with your husband and he with you, but you must BOTH listen to each other.
Peace For You Both!

Posting this here is fine, Wrathoftime does have a good point in that that group has spouses in the same place. That said, we will do what we can here too. Many of us are in relationships of varying kinds and have dealt with some of the stuff you may hit on so by all means feel free to post.

Hi dear, I was a husband once and transitioned to female. My marriage didn't last. I can answer any questions you might have for a trans person. I am very honest and open.

I feel for u I'm going through the same nightmare as u. People have told me I'll get through this but at the moment I'm finding it really hard, some days are better than others but just taking one step at a time. A piece of advice I can offer u is don't look to far into the future it will drive u insane the best thing I could do was really just go day by day c wat happens xx

well I am married and I am not even supposed to act like the gender i feel I am. cause it makes him uncomfortable. which is understandable. I am not so dysphoric that I can't handle that. But it puts me through some discomfort at times as well.
But what worries me, is that in general it puts a huge strain on the relationship, unless the other person is bisexual, cause than on some level it is like being with someone of the same gender. Which can be I think probably just as hard and unnatural also for a person to deal with. So I can tell you, from my living with my husband, I am feeling your pain.
I agree with debbyann, take it one step at a time, one day at a time. But also i think you should be upfront with them about your feelings. Cause that's important too. Also I would say another safe place for you to be emotionally is just where you can be that if for some reason the partnership breaks apart you will be okay. I mean cause it seems like you two are in a precarious place. Just be ready in case.