I totally support Hemant Mehta's first suggestion:
You need to respect the other person even if you don’t respect the other’s beliefs. Talk about religion. Argue about religion. But ultimately, you need to find a way to live with those differences. If you can’t, then maybe marriage shouldn’t be in the picture. [my emphasis]
Christians have the so-called evangelism - coming out and trying to convert people into believing their BS. If Steve *really* loves this woman, I think Steve has the responsibility to help this woman come out from the enslavement of religion. This may be hard, but this is the right thing to do.