If a woman is not a virgin at marriage then that does not mean necessarily that she has slept around in the way you describe.
I think that in requiring your wife to be a virgin you are missing out on lots of quality women, who do have morals, do value themselves highly, do respect themselves. Maybe they have also been in love with a man, slept with him, and the relationship has eventually ended.
Are these women to be judged by men as no longer worthy wives?
If a woman has slept with many men then that is entirely her business, as it is for a man who has slept with many women. Virginity, as TRUE BRIT states, is simply a statement of fact, whether or not you have had sex. It doesn't guarentee a good marriage, or a good future sex life.
The reason why I dislike the viewpoint of men who insist on marrying a virgin is that I think they are placing far too high a value on something that really is of little importance at the end of the day. And in focussing so narrowly on that, they are neglecting to look at the really important things that make a marriage work.
@LAUREN D - Since when was sex 'not a biological need' for women??? I think you will find that for most women if very definatly is!
EDIT - Then I'm not sure I quite get your point. Are you complaining that women will have sex easily with some men who they don't wish to commit to, but will not have sex easily with men they do wish to commit to? I expect that is because they want the second type of man to get to like them first for themselves, without their judgement being clouded by lust. Then when they know the guy likes them for themselves they are happy to have sex with him. With the guys they didn't want anything but sex with, obviously the guys opinion of them personally wasn't as important.
Physical characteristics are also a poor reason to marry someone or not. If you find the person physically attractive then that is all that matters and often that comes with getting to know the kind of person they are, and your admiration for them, can lead to a physical attraction. But to marry someone because he has big muscles or she has a cute face and perky boobs are foolish reasons as these characteristics are only temporary, as is virginity.
Again the important things are your shared sense of morality, beliefs, attitudes in common, same approach to and desire for sex etc rather than whether a woman is a virgin or not.
Personally, I do not think its possible to know whether you are sexually compatable with someone unless you have had about a years experience of sex with them, so I would never advocate someone to marry as a virgin, as too many relationships fail through mismatched sex drives/interests.