When I was younger, I wanted my wife to be a virgin...
But as I got older, my way of perceiving things changed. Last time
I was after physical satisfaction. Now I would prefer emotional
satisfaction, so yeah, I don't mind if my future wife is a
non-virgin as long as we are both very much in love and committed
to each other.
No one's perfect. I'm not, and neither is she. So why worry about
the past? Unless she had slept with MANY guys before...
Then of course, I wouldn't woo her in the first place.
But then again, it depends on situations. If I love her really a
lot, and she decides to commit to me only, then it will not be a
problem. 
