I am sadly realizing that these differences are often irreconcilable. It seems that the chances of having any meaningful relation with someone is inversely proportional to the degree of their conviction. Your ex-husband seems very religious. I suspect that if he merely identified as a Christian for social reasons, attended church once per year, never read the Bible or thought much about religion for most the time, there would be little to prevent the two of you from continuing your marriage. I’m sorry to hear of your predicament, and I know what a horrific impact it can potentially have. My sister seems to resemble your ex-husband, and the situation is profoundly agonizing, and likely terminal.

Forman "Why aren't you working?"
Worker "There is no work to do"
"Why can`t you just pretend that you're working then?"
"Why can't you just pretend that you've seen me working then?"

Number 3 on the list is I think is "Thou shalt not take the name of the Lord thy God in vain.” What could be more blasphemous than lying not only to your family but to god as well? To be fair you went far further down the road of paying lip service to his bollocks than anyone had the right to expect.
Unfortunately, this is not the only case of this sort to be posted on here. It seems that the veneer of Christianity seems more important than actual belief.
The best thing is to be true to yourself and teach your children to do the same. If they end up believing or not, it will be their choice and not something imposed upon them for the sake of appearances.