Certainly, chances of becoming pregnant in such condition are almost 100%. You have to adopt one of the contraceptive methods like oral pills, copper-T, post-coital pills etc or compel him to wear condom. If he is doing violently then it means he does not have feelings for you and taking you as a sex object to fulfill his desire. Such relationship will leave you in pain and remorse in future. Better, leave him and convince your husband to take the treatment for his sexual inadequacies. Take him to Psychiatrist nearby.