Painful/Sore Sex?

It isn't because I'm not wet! That's all covered. It's a different type of pain. When we're having sex in certain positions, at certain angles it hurts really bad. It almost feels as if he's ripping through into my stomach. Sometimes I can deal with it but most of the time I have to tell him to stop for a second and adjust my body at a different angle so it doesn't hurt... Is this a result of him going "too deep"? Is there something wrong with me? Is there any way that I can prevent this from happening?