ooo Good question! It's an important one too because people change over time which is why IMO religion is NOT a thing to base relationships on.

When my wife and I married we were both die bard fundy xians. I was already doing ministry work while I was in the military and doing formal training through the Assembly of God even. Today I'm atheist and my wife is evangelical, generic christian. The only difficult thing has been 1) family, and 2) children. Our agreement so far has been no absolutes but to treat Sunday school and such as a learning opportunity but when we discuss things we say "x teaches this, some believe this, what makes sense to you? and you don't have to be sure what you agree with right now."

My observances about people is that religion has zero bearing on people who have been married over 10 years, especially those past 20+ years. My wife even has an aunt and uncle who are Lutheran, Baptist and each goes to their own church and they've been happily married for over 40 years. I've also witnessed women who attend church all the town fall hard for the leather jacket wearing bad guy bent on "saving them" via the most powerful weapon out there "no milk free" so they convert after they've had one evenings sample of their sweet milk and *bam* they're hooked into the womans trap forever whipped.

Why is the woman (or guy) so easy to "put out" at least once to get that hook made? Because they don't actually believe in their god/religion. If they did they wouldn't be able to have that pre-marital sex (or even marital) because they believe God sees all, well if their earthly dad was in the room would they "open up"? Of course not, yet their faith teaches them God is there with an even greater presence. Therefore they don't actually believe, they merely pick up the banner and don their mask (how appropriate the Sunday dress up is) whenever they feel like.