Your husband appears to at least be a Crossdresser at this stage on the Transgendered Spectrum.. The thing to realize is that this is not his fault or yours. Often this is something that is present at birth not because of something you have done. The problem of course is the secretive nature of the phenomenon.
Many Crossdressers live in a constant state of the fear of being discovered and ridiculed. This means that they rarely confide in anyone, which is sometimes an unbearable burden for them. Often they don't know why they do it.
If he has the desire to BE a woman, this of course is higher on the spectrum and needs more immeadiate attention, and perhaps treatment from a gender professional.
In any event his Physical (or even verbal) Abuse is not acceptable in any way. You may present him with a choice to either get help in private or let the courts do it for him. Above all keep yourself safe even if that means a trial separation.
Its also possible that his hormone levels may be off which is something that can happen to men over the age of 40. Changing hormone levels can cause a profound impact on the brain and behaviors.
So first:
1) He should get a physical exam to rule out Hormone deficiencies or anything else.
2) He should see a Psychiatrist to rule out mental problems such as Depression, Bi-polar Disorder, Obsessive Compulsive Disorder and other mental ailments.
3) He needs to see a gender counselor to at least accept what is happening to him.
4) If the first three steps don't bring him some relief then he needs counseling for his behavior or marraige counseling for the two of you.
5) He should check out transgender sites (not sex sites) for information and to discover he is not alone.
What can you do:
If you don't wish to be a part of his cross-dressing that's OK. Just recognize that he may need to have some private time to himself.
Reassure him. If you love him tell him so.
Realize that you have to give him a little leeway. Dictating that he has to stop will only cause problems for him and you. Besides almost all that purge and swear to stay straight end up going back to it at some point usually worse than before.
Read all you can on Crossdressing and Transgenderism in order to understand it. There are several chat rooms and groups for the Significant Others of Transfolk. Realize that you are not alone.
Get Professional help yourself. You need to talk to someone.
If he is just a crossdresser you have an excellent chance of saving your marraige through compromise and understanding. If he is higher on the spectrum it will be much harder but it can and does work for some.
You are not crazy and you or not nuts. This doesn't mean though that he is. Realize that His pain is real too. No one asks or chooses to be this way.

My Significant Other (S.O.) would be happy to talk to you if you wish. You can write her at lstarkey@comcast.net her name is Linda. I do have resources available in the support links on my site at http://www.lauras-playground.com . There are also Forums and a Chat Room for S.O's.

Laura