Pregnancy often escalates abusive behavior. Let him know that you'll get a DNA test after the child is born (and he can avoid the litigation costs of taking you to court to require one), and that you will be sure to work out issues of custody and support if the child turns out to be his. But until then, tell him to take a hike, and take measures to protect yourself, physically and emotionally.
And if you want to explore your options for protecting your rights if he does turn out to be the biological father, talk to a local attorney. Don't get your legal advice from the internet.