Feeling so Confused

Would you stay in a relationship if your pregnant and your partner is denying the baby and refused to buy anything for that baby. I already have a 3 year with this man and we've been together ever since but for some reason he thinks this baby isn't his because lately I havnt been wanting to have sex with him. he says he refuses to sign the birth certificate and the only reason why he's still around is because of our son that we share together.