Over, you are doing brilliantly, just keep doing it. Play safe, keep acting the way you've always acted when your H is around.
Keep your emergency bag prepared, your phone always charged, a stash of cash and important documents(even photocopies if the originals would be missed), your car keys within easy reach, etc... Don't hesitate to call police or your security if you need to...don't think it has to be a matter of life or death before you call.
Tis normal that, as you go through a calm period with your H behaving nicely, you start to have your doubts about whether you've imagined it all. Just remind yourself that this is all part of the pattern of abuse. He will turn nasty again, you just don't know when.
The internet security advice given by the others is great, and with the preps you are making...if he should discover anything you won't be caught by surprise this time.
Am another one who's thinking of you.