It sounds like you two are doing well. The most common advise you will hear from the poly community is to communicate well with each other. Beyond that, set bounaries that you feel comfortable with for now with the idea that they may change over time as you two experience and learn more.
Making sure everyone is informed is a great key to keeping drama and other issues from getting out of control.
If you start dating someone and your husband starts to get envious, you could try to help set him up. The biggest thing is to learn what your feelings are and communicate them. That works through a whole lot of issues.
I am glad you were able to shake off a religion that did not work well for you. One of the saddest things I see is someone tied to a belief system that makes them sad, miserable or unnecessarily confused.
I wish you well.