There is a good chance you're bruising the cervix if your husband is well-endowed enough to "bottom out" during sex (where the penis pushes into or behind the cervix). If you aren't experiencing lengthy periods of bleeding or any additional symptoms, then I wouldn't worry about it and just kind of get used to it (does that sound as horrible as I think it does?).
You can get a cervical procedure which can bolster the tissue but it involves sutures and isn't likely to be a permanent solution. If rough sex is your guilty pleasure, then you have to take the good with the bad.
I've had my cervix bruised so many times it could qualify as an NHL superstar, but I've never had any bleeding. (Though for clarification, I've had over nine surgeries in that area so it may be tougher than most.)