My wife and I did not live together until after we were married. We dated all four years of high school and got married the week after I got out of Boot Camp.
We have been together for 36 years and have four daughters and ten grandkids.
My two oldest daughters are both already divorced and both cohabitated with their ex-husbands before marriage. But my two youngest both cohabitated with their current husbands and are still married.
So...I don’t know.
That's the norm today. Unless you're a Mormon or some other religious group.