Its just an arbitrary rule of the Church. The Churchs teaching on cohabitation is not an “arbitrary” rule. Living together before marriage is a sin because it violates Gods commandments and the law of the Church.

Is it a mortal sin to live together before marriage?

Living together in itself is not a sin, but cohabitation (living together while having premarital sex) is objected to by the Catholic Church because it disposes all couples who do live together before marriage to mortal sin (partaking in sex outside of marriage), which in turn can be detrimental to our spiritual lives

Is it bad to live with someone before marriage?

About half of U.S. adults (48%) say couples who live together before marriage have a better chance of having a successful marriage than those who dont live together before marriage; 13% say couples who live together before marriage have a worse chance of having a successful marriage and 38% say it doesnt make much

What the Bible says about he who loves to sleep?

“The Bible says, He who loves to sleep and the folding of hands, poverty will set upon you like a thief in the night. ”