Help pls....why does it hurt when i have a ?

sorry if i ask too straightforward. I don't know how to put it in any other ways. When me and husband have an , if he does it a little bit hard or deep, my stomach would hurt ad my lower abdomin (how ever you spell that)...and especially i'm on top, and ithurts really bad. not my but my abdominal...does anyone have similar problems and do you know what is it or what is causing it?.... thank you very much in advance