Exactly, and it pisses me off. If you love this girl and think you might have a future with her, no one would blame you if you fooled around, but the end married her, or at least don't ruin her reputation when you break up. I lost a huge deal of respect when my friends said that they wouldn't marry their girlfriends. One quote from a friend of mine 'ba3d kol 2l 3melto ma3ha, wel marat 2l wasalt-ha 3a beet-ha ba3d 2l 12 beleil, bedak yani 2tjawazha? bterda 3a 7alak tetjawaz sharmo6a?' Not the exact quote, but that some of what I remember of it. It was when I asked if him if he would marry his current girlfriend. That girl is a virgin, yet he called her a sharmo6a because she stays out late and they did some minor stuff like kissing and touching, I can't imagine what he would call her if they did worse!
As for the living together before marriage, I think I disagree with you there, Yamen. I know it's against our social morals, and against religion (or so it is) but (Speaking of myself) If I want to spend the rest of my life with someone, I at least would like to know how it will be to live with that one. Dating isn't enough and doesn't reveal everything. When you live together before marriage, you have the power to stop what would be a big mistake (biggest mistake of your life?), or you can have the choice to carry on and marry after knowing that this is the human you want to live to the very end of your life with. Divorce ain't easy, especially in christianity.
How many girls end up living a nightmare after the honeymoon when they discover that they married a wife beating scum?
Such stuff could easily get known when living together before marriage. Dating doesn't tell the whole story. I know like 5-6 cases where girls ended up marrying a guy that beats them up, a guy that locks them up and goes marry another one or even leave the country and etcetera....
Such things are hard to discover, and usually get known after a marriage. How could you tell if this guy is a wife beater or not? It's almost impossible to know (Unless he was previously married and did the same, and has a reputation of it)
As I said, I'd like to live with the girl I want to marry for at least few months before I marry her. Even tho that would work against my advantages, as I doubt any girl would manage to sleep more than hour next to me. She'd wake up the next morning with a black eye at least.

Although it can be solved by sleeping on separate beds. (I'm quite a karate champion when I sleep)