Same father sibling or half sibling

What is your advise if I am no longer in love with the father of my 18 month old but want my LO to have a sibling. Should I have another child with him for the sake of my LO having a sibling of the same dad or should I look for someone else. I don’t want my LO to have a step sibling but I don’t know if I will be able to avoid it. Partner is not emotionally available. He made a comment of “I finished you” when LO was about three month meaning I will be tied to him since I now have a child with him. We have been intimate once since LO was born. He provides anything we need but he is never at home. I feel like a single mother. The only thing he does is provide for us financially. We are not married but have been together since I was 19. I am now 37. This is our only child as much as I know. What do you all think I should do?