I posted a similar thread in the "Sex" forum, but then I thought t might be more appropriate for this one instead.

So... let me start with a little background:
I've been having sex for about two years. (I'm nineteen.)
My first boyfriend and I had sex only a few times a month. It never hurt or anything, but I always noticed a small tear on the bottom of my vagina after sex. We tried using lube to see if that would prevent the tear, but it didn't.
My current boyfriend and I have been having sex for about two months now. We have sex a lot more often, say a few times a week. We use lube, try different positions, and I'm still tearing.

Every time I have sex, I get a deep cut on the bottom part of my vagina. It doesn't hurt during sex, but it does after (and sometimes makes using the bathroom painful).
Is this kind of thing normal?? What am I doing wrong?