HE IS TOO BIG!!!

I've recently started seeing this guy who is just amazing except when it comes to sex. We both enjoy very tough, passionate sex with him being the more dominant one. However, his penis is too large to mess around with. I'm talking 8.5-9 inches. I've gotten an IUD, and the doctor who placed it said I have an abnormally short vaginal canal. I never thought this would be a problem until now. We finally got around to having sex, and he went HAM. I had to make him stop because I started crying. We took a break and tried a lot of different positions, but NOTHING worked. Even when he was being gentle I felt like my cervix was being hit with a hammer. He was really understanding and did his best to accommodate me so he isn't the problem. His penis is. Has anyone else dealt with this? Are there any positions that put less pressure on the cervix? My body feels absolutely terrible now so any advice or thoughts are much appreciated