When I say "more than 3 months" it doesn't mean, exactly 3 months. It means longer than a short period of time so that you have a pretty well established idea as to who he is. And the phrase "sleeping around" implies sexual activity with more than one person in a short period of time with no relationship attached.
Fair enough, JediGirl. But I can tell you that as a guy, I wouldn't look for a mate who had spent her highschool years with numerous boyfriends with whom she'd had sexual relations (even if she'd waited your prerequisite three months). Your trouble is, your sexual morality has been reduced to 1) getting to know the guy over a short period of time and 2) caring about him. I know and have known many guys who would take quick advantage of such a situation. We obviously come from a very different worldview with regard to sexual morality. If my daughter should find a husband who truly loves her, and saves herself for him, I honestly do believe that she will lead a far happier (and less dangerous) life than your daughter, who will be off having her safe sex with different guys that shes happens to care for. My son-in-law will value what my daughter will have achieved and has given him in a true lifelong commitment to marriage and family. Your future son-in-law will always know there was this other guy, and this other one, and this other one... He will always wonder just how committed she is, knowing all the guys she 'cares' about in her life.
I wonder how many of the guys with all the moral underpinning married a girl who wasn't a virgin.