I think that sex before marriage is a must. and the funny thing is, because of the exact reasons posted above.
To be able to share a happy marriage you will have to "know" the person as good as you can.
and since sex is the most intimate situation you can get in with another person (or more ) you will have to take the step first to be able to judge right. anything else would be just guessing, if you are honest.

i also disagree with the statement that sex before marriage make you leave and lose some of yourself every time.

Imagine meeting a stranger and having a good conversation. something as personal as sex for example can be.
this, like sex, can enchance your life dramaticly if you allow it. it doesnt take away somthing from you but adds lots to your life.

you can decide not to have sex, drink or eat lemons before your marriage. if this is what you want nobody should have anything against it or say anything against it.

but it also wont make your marriage better because of that or more honest or true.

how many good or best friends did you have in your life. due to our lifestyle and speed they come and go. And just because i cant spend more time with my best friend from highschool aynmore his friendship was not wrong, nor took it away something, nor do i want to miss those times.

as the people you never wanted to meet, also those who you had more intimate relationships with, will form your life.
they help you become the person you are. but this requires you to accept it.

have sex!
cheers