Here's my view on pre-marital sex but please keep in mind I come from a different generation then some. Like most, before I had sex I thought the right thing to do was waiting till you got married to have sex. High school soon changed my view point on this.
Coming from a broken home I was never really interested in getting married because me and mostly everyone I knew at the time, parents where divorced. As I grew I had a few relationships along the way that I thought it could be the one. Then the sex thing started coming up in the relationships.
Believe it or not the first girl I was ever with made a point to me which I still remember to this day. You might not agree but I live by this now. She said "What's The Point of Waiting To Have Sex Till You Get Married? What Happens If The 2 People Don't Click Sexual Together Then They Have No Chance" which I thought about then it did kind of make sense. See in my eyes if the 2 people don't have "GOOD SEX" then the marriage doesn't stand a chance because one of the people if not both will be dissatisfied and look else where for pleasure then which causes cheating then divorce.
So basically what I'm trying to say I think personally if you're serious about marrying someone you have to know if you're both sexually compatible before the marriage go's through.
I disagree though. Taking whether you feel it is moral not out of the equation I feel you are missing a fundamental point. You only are learning the physical aspect of intimacy from your test drive scenario. Which no matter who you are will only captivate you for so long. Maybe years or maybe months. But two people who enter a marriage out of true commitment and actual love will experience sex on an entirely different level. A level that will grow and last forever.
The fact that there are people too quick to marry and view sex as an activity, like going to the movies is simply cheating yourself. For those who have experienced what I am saying can confirm my point.
Statistically people who live together before marriage have a divorce rate of quadruple that of those who do not.