Welcome JB.
If you can get him to open up his mind and see his religion as the sham that it is, you have hope. If you can't do that, then leave, or you will only have regrets. Do you really want to be married to someone who will let your child die before giving him life saving blood?
Also, why should he wait until after the marriage in order to get baptized? If he really thinks is the truth, why hold back? You have a right to see how his marriage to the religion might impact your relationship before you commit. He wants it both ways.