Congrats on connecting with your brother. I am happy for you! I hope you can keep talking with him. It is easy when going through this kind of stuff to lose focus on everyone but your spouse. Hope this goes well, for both you and your brother.
On the email, I doubt from your posts that your H would say anything either, but they can and often do pull back by simply withdrawing and saying nothing for a while. He may be hunting for dirt, or he may just be snooping. Just because he says he doesn't feel attached to you.
I did have one thought this morning about how you could use your email to DB your H. What if instead of a fictional love intrest, you had a fictional 'life coach' emailing you? If you have a friend who could help you do this, great. If not, just be your own coach. You could talk about getting a life, detatching in healthy and loving ways from 'people' who hurt you, how you are taking care of yourself, maybe even get general advice on why starting a relationship while in crisis is not a good idea (maybe H will take a hint), get encouragment and inspiration, the list goes on and on.
If you did this, I would be careful to keep it focused on YOU, not your relationship. Also, keep it positive and a little more business like.
If you do continue to allow H access to your email, be very careful what you write to anyone. I don't know the laws where you are at, si I don't know if it would effect things if H files for a D. He may try to use anything he finds there against you. You may want to set up a seperate account to deal with any legal or other sensative issues that come up. Just in case.