dating

"Never date anyone you wouldn't marry". I've heard that all my life, but it wasn't until recently I truly began to understand why. It seems as much as I heard this people forgot the ending part of the quote, "...because you never know how hard you will fall for someone". Everyone at some point thinks they can control their feelings, but there becomes a point to which, control is lost and the heart takes over.

Another thing about dating, that can simply boggle the mind, and if anyone has the answer to this illogical way of thinking, it would be greatly appreciated: Guys (most, not all, but the fair majority) want to date girls who put out, because they are more fun or something. But they want to marry the good girls that haven't gotten around and slept with every guy on the block. Where's the rationality in that? They want a girl to wait for them if they plan on marrying her, but any girl prior to that needs to fulfill that guys needs?

Someone help me to understand! Please! I am not trying to "hate" on guys, but just trying to understand what makes them think this is ok. I am sure some girls think the same way, but it seems to be a more common mentality among men.