You don't actually need to lose your virginity for your hymen to break as well though. Mine did when I started to use tampons for the first time, so I can't say for sure what actually happens to it. It can also break if you do certain activities or sports too. There's a chance that you might not even actually have it anymore. A lot of girls don't actually notice it breaks because there isn't always bleeding or pain involved when it does.
ps, it's "vagina," not "virgina." From the latin for "sheath," it has nothing to do with the word "virgin." Those Romans named about everything after something military or martial, a knife sheath is what they were thinking of. :)
I think that would be an interesting question for a gynecologist. I don't think the hymen is (as in popular culture) like the top of a drum or a piece of Saran wrap stretched over the top of a glass, after all, it has a hole in it already to let the menstrual flow out. This probably means that that hole gets stretched, and with continued sex it either rips a little or a lot, to make room for the (tampon or) penis. I think if the tissue were thin it might essentially scab over and the scabs fall off after a time, but if it were thick it would just stay there to the sides of the vaginal opening and be part of the whole fluffy area down there. Don't know for sure, though.