I have always maintained my stand on premarital sex since my days in school and immature as it may sound for having formed it so young, I still stand by it. No, it was NOT to cover up for a careless act!
I believe sex is welcome when 2 people are so comfortable in a relationship that if and when they do indulge in this act of togetherness, they ought to be able to come out of it with a straight face and be able to see each other in the eye just as they did before having sex. If that's possible, sex is not an issue - Its but an extension of one's natural self.
I dont see how marriage acts as a license to sex. Personally, I think its ridiculous.