Sensible, safe sex, in my opinion, should be engaged in. Why? Because, as you get older and are ready to settle down, you will look at your potential sole mate, not for sexual reasons, but for what they have to offer mentally and if they are compatible. When religion restricts this, and yuo must marry to have sex, I believe that you doom a marriage at the outset, because these young folks marry out of lust, only to have the rose colored blinders pulled off later, and regret the entire arrangement...
Mormons, and JW's, et al are all guilty of this. Met so many messed up marriages in these religions, whereas, on the outside, they tend not to be that bad - and if they are, they get divorced. Not in those religions, its for LIFE even if you don't love each other, only if someone takes the bullet and commits "adultry"...