When he applies for an H4 visa for me, will I still be able to enter the US using my toursit visa until my H visa is issued?
Once you get married, you will be able to apply for H4 visa in canada, that will provide you with a status to live in US with him, till he retains his H1 status. You cannot work during this period on H4 visa. I am not sure about the NAFTA provisions for canadian PR, I believe they apply only to canadian citizens. As long as you have tourist B2 visa, you can enter US (usually for a max period of 6 months). But once u get H4, ur B2 will be cancelled.