I get rough during ejaculation. Why?

Hi

I have a problem during intercourse.I get rough during climax and start moving too rapidly. My wife tells me later that it hurts her.

It is especially when I am ejaculating. At that point I am unable to keep a control on myself. I move too rapidly , I press her breasts and buttocks quite roughly and am not sure what else I do. Even after I ejaculate this continues for some time before I come back to normal.

Is it normal or I have a medical problem? Why do I find so difficult to control myself during ejaculation ?