I am so sorry Bluechair.
I remember when your husband was upset with you and wanted you to support his choice about staying at your house and not his parents. I thought "oh he must have a stash at the his house." I was hoping I was wrong. Addicts are just so manipulative but it's hard to see when it's someone we love.
I have been amazed at how cunning my husband has been. He actually had pills delivered to our mailbox at night.
I agree with above posters. Your anger is understandable and your guilt is all too common.
Your husband asking you not to tell his parents is a huge red flag. In fact, I think he needs to tell them, not you. No more secrets in the future, honesty for all is imperative right now...as always.