Does the father have legal rights to the child if were not married and i didn't put him on the birth certificate and he dumped me when i was pregnant

Me and this guy only dated for 3 months he left me for another women. i found out i was pregnant after that. i tried telling him he kept denying it was his i didn't put him on the birth certificate.now hes harassing me saying nobody can stop me from seeing her even know i have Nothing to do with him because hes not a good guy