The sex thing really is a silly reason to dump someone. I'm not DEFENDING our tendency to demand sex, but the least I can do is present it from my point of view:
I once dated a girl for about a year and a half who was a virgin when we first met. I knew I was falling for her, and I suspected she might reciprocate my feelings. But at the same time, I felt the only decent thing I could do was communicate that I was more experienced and that, for me, sex was something I did expect in a relationship. For us to be together, I needed for her to understand that and the pressures that go with it.
So in all reality, she probably wasn't "ready" when she lost her virginity, but the truth is she probably never would have been. In her case, "ready" and "willing" were two separate things. For most guys to push those boundaries could mean being brought up rape charges, and in our case the dialogue about sex was open enough that I could safely avoid any such violations. She knew the risks and was willing to take those risks. I told her outright if she wasn't comfortable with that then we should end the relationship before things progress beyond what she could handle. She stayed with me, and after a few months the inevitable happened.
If that makes me a pig, then so be it. But I think it's much better for a woman to know what she's getting into and make a choice she can live with rather than for a guy to tell a girl what she wants so that he might get a chance to take advantage of her. Guys, like it or not, will generally tend to demand sex. About the only way you can avoid that is to stay cloistered in some kind of religious institution (like a Christian church) and meet a like-minded man there. I actually HAVE known couples who were both virgins until they got married. The girl I mentioned above, in a similar way, decided after we broke up that she didn't see sex as all that important. The last I heard, she was dating a younger guy who is a virgin and she has no problem keeping him that way. I admire her for that because I simply lack that kind of self-control!
The sad fact remains, though, that most guys who have had sex in a previous relationship will tend to expect it in future relationships. When you go out with a guy, you are going to run the risk that he will pressure you or even seduce you.
Saving yourself for marriage is a NOBLE thing. But at the same time, having sex is NOT the worst thing in the world. I'm a particularly religious person in spite of how I might have been in the past. Even in the Bible, particularly the Old Testament, sex is NOT regarded (as commonly thought) as automatically punishable by death. What IS punishable by death, in a sexual sense, is taking something (a woman's virginity) that doesn't belong to you (if you're a guy) or isn't yours to give (if you're a woman). If, for example, you (as a woman) claim to be a virgin on your wedding night and you aren't, then you're lying about one of the worst possible things to lie about. So, of course, they're going to kill you. If the man loves you and already knows your past, then he might be quiet about it and no one ever has to know. But if that is a problem, then he can leave and take his business elsewhere and no harm has to come to anyone. Rape is deserving of death for the man who commits it. According to the OT, though, it is POSSIBLE to forgive rape if the family can agree to let the couple get married (in a day of arranged marriages, this is hardly likely, but possible). It is possible in many instances that a couple who love each other can be forgiven sexual sin if they are allowed to marry--the Bible indicates no reason why they shouldn't. Unmarried sex with slaves in not forbidden, but there are probably very strict reasons why anyone WOULD take a slave as a lover--I'm guessing most likely for reproductive purposes, not just simply mere pleasure; there are documented Biblical cases for that, as well. So while the Bible does emphasize that we should avoid sexual immorality, it also doesn't cut out sex entirely, either. In any case, it's a "proceed with caution kind of situation."