Avoid the topic when you can, it's not something that'll be pretty unless handled in a calm discussion which Well, people as a whole tend to be pretty immature with big topics.
Breaking up with someone solely because of religion is something people condemn alot on this sub when its a Mormon breaking it off with a non Mormon, but if floats both ways.
At what age do you baptize.
Just remember that you chose one another.
However, I believe there are rules set, and we receive certain blessings when we obey said rules.