Tears above vaginal orifice. Little Pain. Should I be concerned?

Okay, so I've looked through quite a few of the board listings and none of them really seemed to reflect what I've got. I have been with a three guys, and as I've progressed, so has the general penis size. The guy I am currently with is 7.5 inches long by 5 inches around; meanwhile, I'm rather petite. I'm not entirely sure that the tears that I'm getting are strictly from the size issue, as I occasionally got them with my first partner who was considerably smaller than guy number three. My symptoms are thus: torn tissues directly above the vaginal orifice (generally about 1 to 2 mm deep, and never bloody, just more like dents in the tissue), no pain except during initial penetration during sex, certain positions which cause the shaft to rub directly against the tears, and occasionally during urination. Also, as a side note, the pain itself may continue during sex, but if it does it usually adds to it since I'm a bit masochistic; it's really just the initial pain that I really notice, as I'm not "warmed up" yet. I don't have any STD's, nor does my partner (we've checked). I'm thinking that it's mostly a matter of trying to put something big into something small, and that the best cure for my problem is a great deal of lubrication. Anyway, I know that on the boards a lot of people have been saying to stay away from sex until the tearing heals, but honestly that isn't an option. From previous experiences with trying to "let it heal first", I've found that it takes nearly two weeks (or more) for even minor cuts to heal up half way due to my nearly "perma-wet" vagina. In addition, my partner and I both have unusually high libidos and it's hard enough dealing with the week I'm on my period, so to wait for a month or two between sexcapades for tears to heal is utterly out of the question.

To be honest, I really don't mind the tears that much, especially since the pain sometimes adds to intercourse and is often only minimal in intensity, so I can deal with it if there's little I can do aside from investing in an endless supply of lubrication. I'm mostly coming to you because I'm curious if this is 1. at all usual or common, 2. treatable, and 3. possibly the causes. The next time I'm home from college I plan on making an appointment with my gynecologist to see what she has to say on the matter, but until then I wondered it you had any answers? Thank you in advance for any light you might be able to shed on the situation!