Religion and beliefs are one thing… but how far can it go with a girl? I am not going to be a dick, and you dont have to answer if you dont want to. Because honestly you seem to have a good head on your shoulders, and if your gf does too, I don’t see the harm in sharing each other’s body in a smart, loving & safe way.
Your gf looks very nice, and if you didn’t post the age, I swear she would be over 20, she looks very grown up and responsible in that second pic.
EDIT BTW I have been with my girl for longer than most people have been married! I am not a player at all, so I think I know where your coming from.